By on August 11, 2021


The Fast and Furious franchise gets a lot wrong when it comes to tuning cars – but what thing it gets mostly right is the spirit of family that comes with that lifestyle.

Normal people don’t tune their cars,” the great Jack Baruth told me, years ago. “Normal people buy Camrys and don’t think about their cars at all until it’s time to buy their next one.”

He’s right, of course, but it’s nice to feel normal, and I’ve surrounded myself with a family of go-fast car and motorcycle people ever since. Recently, one member of that little family decided to sell his daily driver – an utterly unmolested and squeaky-clean W211 Mercedes-Benz E55 AMG – and that’s where my trouble started.

Like any good friend – sorry, family member –  I wanted to help. I got some of his pictures and wrote the following post on the local Facebook dads’ group:

OK, dads, this is a special one for anyone interested in these cars. [Tuner guy’s name deleted] believes you don’t tune your daily, and has owned this car for several years. It’s clean, bone stock, and the last of the big blown AMGs. Reach out if it’s your bag, baby.”

The first comment, right out of the box, had nothing to do with the car, nothing to do with the price, and nothing to do with the car’s well-known owner. It was this:

You don’t tune your daily? Had to check to see if this was posted in the mom’s group.”

It was a comment which – my knee-jerk accusations of sexism, toxic masculinity, and baby-dicks aside –actually did lead to some interesting questions being asked. Namely, why shouldn’t you tune your daily? And, considering I’ve spent the better part of my career trying specifically to convince people to tune their cars, I felt like it might be interesting for me to try to answer that question here in a frank, open, and honest way. You know, like, I could tell the truth. About cars.


Now, when people talk about tuning their daily drivers and building them for performance, the general assumption is that we’re not talking about six-figure German muscle cars or twin-turbocharged Japanese techno-rockets here. I’d argue that those guys have the money to break a transmission here or there and deal with it, if begrudgingly so, so let ‘em. Instead, I’m talking about the guys and gals who start to earn a living wage for the first time in their lives and decide to spend some of their newly-earned dollars on high-performance go-fast parts for their – I dunno, let’s say it’s a 2009 Mk6 VW GTI.

At 12 years old and with something around 120,000 miles on the odometer, that ’09 Mk6 GTI might have plenty of life left to it. That’s especially true if it’s been properly and meticulously maintained – but it probably hasn’t been, and that brings me to this simple explanation for ECU tuning – commonly called “chip tuning” – that I was given as a fresh-faced, doe-eyed innocent on one of my first days at RENNtech way back in the early aughts.

“The manufacturer builds in x amount of performance in their engine, and n reliability,” the explanation went. “And whenever you tune a car for more performance, you’re subtracting from n to get more x.”

I’m sure you can see where I’m going with this, but that’s probably because you’re a mature human who understands that “Stage 1” and “Stage 3” are just marketing terms meant to capitalize on the popularity of Gran Turismo, and don’t have anything to do with objective reality. In case it’s not obvious, I’ll spell it out: that 12-year-old car doesn’t have enough n left for you to get the amount x you want out of it, and you should leave it alone.

And that’s just engine tuning – we haven’t talked yet about suspension tuning with lowering kits or stiffer springs that put different loads on different parts for different amounts of time than they were designed to handle. What about brakes, wheels, and tires? If you’re making your car go faster in a straight line, how are you planning on managing that extra speed once it’s time to stop or steer? Can you afford to do what’s right, here, or are you deciding what the engineering priorities should be based on some dubious metric like, “APR is having a 20 percent group buy on …”?

Of course, I’m making a lot of assumptions here. I’m assuming that you’re driving a 12-year-old GTI because you can’t afford a new one. I’m assuming that you probably don’t have the ready cash to replace a failed turbocharger or scattered DSG, too. Finally, I’m assuming that you have not gone from stem to stern on the thing replacing all the ball joints, bushings, bearings, or any parts that start with any other letters of the alphabet, either. I’m assuming that the car gets you from A to B well enough, and you’re gambling that it can handle whatever extra strain you’re about to throw at it.

Which begs the question: if you haven’t gone through the car from bumper to bumper, how do you know it can take it?

You don’t, and you used to see the results of these failures all the time on forums like 6SpeedOnline years ago, with for sale posts about cars that were just about to pop.

“I’ve had a lot of fun with this car, as you all know from my other posts and videos,” they read. “But it’s time for me to move on to my next project, and I want this car to go to a good home …”

That’s another rude awakening coming to first-time budget tuners. All that money you spent on your car? Not only will you not get it back when it comes time to trade in that car at a dealer, but you’ll also probably get less for your car than someone who left their Mk6 GTI stock … it’s an especially painful realization because, to you, you’ve genuinely tried to make the car better. It’s the same hurt I’ve seen on the faces of guys trading in their customized Harley-Davidsons. Some of these guys spend $20,000 on a bike, another $20,000 on chrome and handlebars and paint, and just die inside when you explain that, all that money they spent getting their ride “just right” really took its market appeal from “as broad as possible” to “you are the only person who could possibly love this metal flake yellow and brown monstrosity – and why is there a werewolf playing the guitar on it?” You know?

You do know – but before I let you go; I will acknowledge that there may be some exceptions to the whole “you’re going to break it” thing. And, since no internet argument is complete without a villain, I’m going to give you one: The marketers.

At least, I assume it was the marketers who decided that a 2011 Mercedes-Benz SLK350 could reliably and dependably and responsibly handle 300 hp when that same, fundamentally identical powertrain in a less expensive C350 of the same vintage could only handle 268 hp. It shouldn’t be much of a surprise, then, to learn that my favorite “tune” to put on the C and E350s back then was just the stock SLK350 file. It made the cars noticeably more responsive and heck, the dealer could even scan the thing and it wouldn’t trip any alarm bells. Why would it? It was a valid MB file!

There are a few other weird deals like that. The 3rd gen Toyota Supra had an easily defeat-able fuel cut that limited its output as part of a bizarre “gentlemen’s agreement” that Japanese automakers once had to not sell cars with more than 280 hp. Removing that effectively changed nothing, but “released” about 40 wheel hp, so that was nice.

Still, these are exceptions that prove the rule – and, yes, you might find a few VWs or Buicks that have been neutered by the marketers to protect the price gap to their more expensive Audi or Cadillac siblings, but if you can’t afford a new one, well – you probably shouldn’t be messing around with an old one. In fact, that’s good advice: before you start tuning your daily, buy a backup daily to get you back and forth to work. That could even be something interesting and fun instead of boring and lame, as Corey Lewis has done a great job of pointing out.

So, be smart. Don’t tune your daily. And, if you already did, I’m sure your car is different and you’ve made a fine life choice there. Have a great day!

[Image: Joyseulay/]

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48 Comments on “Opinion: You Should Not Tune Your Daily Driver...”

  • avatar

    My ’02 TDI got tuned and upgraded injectors at 200k miles. Yes I had to upgrade the clutch, but Jebus the torque is fun. At 400k, it’s a car that I still love.

    Choose your tune, Wisely.

  • avatar

    As someone in California looking at a now unregisterable Evo VIII in my driveway, I agree.

    • 0 avatar

      F*** the PRK.

      • 0 avatar

        Just curious…is there anything in any other state DMV statutes that might render a vehicle unregisterable? If so, be sure to call them out too.

        • 0 avatar

          As we saw with the Mitsubishi problem in Maine, it seems these butt wipes can just arbitrarily do whatever they like.

        • 0 avatar

          Enthusiasts hate CARB. They could easily make our lives 1000x easier without compromising their mission, but they have to be petty little fucks about absolutely everything.

          • 0 avatar

            Like most of what gov’t does, what starts out altruistic turns to dog excrement. CARB should have been dismantled in 2000 after 25 years of success but instead of course we’d rather purse diminishing returns.

          • 0 avatar

            I’ve always said they should allow you to declare “modified”, then be tested on the sniffer. Then base your reg on your actual tailpipe emissions + a mileage fee. I’d pay a extra few hundred a year to be able to drive the racecar to the gas station and carwash.

          • 0 avatar

            They’d rather go after the 20 guys having fun than the city bus companies and construction crews that cause 100x the emissions.

          • 0 avatar

            CARB is no different than any other government agency. Their hiring profile are people who follow orders with no questioning and are mostly incapable of independent thinking.

            The end result are organizations like CARB led by people who now rely on a government pension, have no incentive to improve the organization and who’s purpose is to continue rather than advance.

    • 0 avatar

      Dude– that sucks. Do you have a tune on the stock ECU or a piggyback? Because I think the piggyback will still pass.

  • avatar

    Not to be too much of an old guy, but with factory power outputs what they are (and have been for so long now), the appeal of tuning makes a lot less sense to me than it used to.

    250-300 hp front drive hatchbacks have been around a while. So have 400-500 hp muscle cars. These are reasonably attainable to a variety of budgets, whether new or used.

    Adding 30 hp to a 200 hp car was kind of a big deal, when that was the best you could get. Adding 30 hp to a 400 hp car, less so.

  • avatar

    The 2020/21 GTI and GLI 2.0L turbo 4 makes 228hp with 87 octane. The same engine in the Arteon running 93 octane makes 268hp with some additional boost. Same thing with this engine in higher performance Audis. I’ve started researching what it would take just to unlock those 40hp in my engine, how much it would cost, and what kind of long term issues I might be looking at. The DSG should be able to handle it. But I’m assuming that if the mod is made, kiss the warranty goodbye and I’m doubting I want to do that.
    Anyone out there make this change in a new VW/VAG car? Just curious about your results and findings.

    • 0 avatar

      I suspect the person who ended up buying my old A3, which has the GTI motor, modded it. This is what owners of thirdhand A3s are wont to do. God help him/her.

      No way would I ever mod an under-warranty VW. I’d consider modding one out of warranty if I were an ASE certified mechanic with a crudload of disposable income.

    • 0 avatar

      “The same engine in the Arteon running 93 octane makes 268hp with some additional boost.”

      Are you sure it’s exactly the same engine? Does one use a forged vs. a cast crankshaft are the valve stems, seats, cams, all the same spec alloy? From what I understand the up the power and run it through the computer and it may say we need to spec an alloy with 2% more manganese. The design of the engine is the same but the material specs are different.

    • 0 avatar

      That arteon is running the previous golf r 2.0 (detuned), while the new Gti’s have an updated version of their own engine. VW changes waaaay more parts than you ever would want to for 40hp. Just get a stage 1 file and/or swap out the turbo, they are interchangeable.

  • avatar
    Land Ark

    The Lexus IS300 engine is identical to the IS350 engine, just tuned differently. If I were to keep my old, now gone, 300 I would have tried to get the 350 tune. I find that way of differentiating models bizarre.

    My 2007 Legacy GT wagon is tuned to “stage 2” which means I replaced the cat with a high flow one and installed an out of the box tune from Cobb. It also has non-aggressive lowering springs and a larger rear sway bar. My wife had a 2009 Legacy GT that was completely stock. And while my car is faster, more rare, and arguably more desirable I know that the ease of selling her car would far outweigh what I would see trying to sell mine because of the modifications. Fortunately most of what I have done can easily be reversed but… will I want to deal with that when it’s time to sell? Probably not.
    That said, my car is much more fun and responsive to drive than hers was while, with the limited amount of power added still being very noticeable, it has been proven to be reliable. And there is also the common discussion among LGT people that the stock tune has a tendency to burn valves and should be changed by everyone, not just Tuners.

    I also have a 2006 GTO which, frankly, does not need any additional power than what was provided at the factory. It’s something along the lines of “if it’s too loud, you’re too old,” but instead it’s “if it’s too fast, you’re too old.” To me, tuning that to add more would be overkill. As it is, I can get myself well outside of legal and responsible speeds so fast that were I to witness myself doing it I would wonder where the police are when you need them. Why would I need more?

    • 0 avatar

      Preach my Stage 2 LGT wagon brother! My 05 LGT wagon was tuned within 6 months of buying it new. Fifteen years later still running the original turbo and no major issues whatsoever.
      I agree with the basic premise of the article but it really matters what car you’re starting with and how extreme you go with mods.

  • avatar

    Eh, I think tuning your daily entirely depends on what tunes or mods you make to it. My daily 00 LeSabre has over 240,000 km’s (145,000 miles)and other than the meticulous maintenance I’ve given it during it’s time with me, I’ve also installed heavy-duty slotted and drilled front rotors for better stopping the old boat, a Transgo shift kit to get rid of the stock overlap shifts making them slightly firmer and extending the life of the 4T65-E transmission (original), and the engine has a ZZP power log front header and 1.65 rockers instead of the stock 1.60. It has slightly more power, but better yet, I’m getting around 65-90 km’s more per tank in the summer and 25-45 in the winter ever since those mods. I’ve heard other other vehicles getting better MPG with performance mods- I’m under the impression that mild mods to a daily are perfectly fine, even if it’s as little as a 91 octane tune for a modern pedestrian honda four cylinder or Camry V6.

    • 0 avatar

      “I think tuning your daily entirely depends on what tunes or mods you make to it.”

      I agree. Taking a Grand Marquis and putting P71 or Marauder stuff on it doesn’t seem like a big deal and brake or tire upgrades are almost always a worthwhile change.

  • avatar

    I guess I am a very pragmatic person, but I never understood why anyone would dump so much money into modifications when they could just use the money for a nicer/faster car to begin with.

    The tuners/modifiers, don’t have a lot of actual logic behind most of what they do in my opinion, it is an emotional thing, a connection to the vehicle…..I dare say even “art” in many cases.

    • 0 avatar

      That is true. When I bought my Suzuki DRZ400SM I found the depth and breath of aftermarket parts mind-numbing.

      I read an interesting blog by a fellow who owned various iterations of the DRZ. He felt that one should do minor low dollar tuning and modding. His point was that if you want more power, light weight, and better suspension just buy a KTM or Husky.

      I felt that way with sport bikes. My litre class bike bone stock could easily outgun any modded 600 or 750.

  • avatar

    For the purposes of this editorial are you saying that tire, brake, and suspension changes aren’t “tuning”?

  • avatar

    You seldom use the extra power, handling or braking capability created by mods in daily driving. But then again, you seldom use the extra power, handling, or braking of a Veloster N compared to a base model Kona in daily driving either, so why not get the Kona? People modify cars to enjoy the experience of a modified car. If you’re a car person, you get it. If you’re not, you won’t.

    There is a such thing as a good and a bad tune for a street car. Generally speaking, don’t do engine mods that hurt low end power. Don’t do exhaust mods that make the car extremely loud. Don’t do suspension and tire mods that make the car ride completely stiff or, worse, make it ride so low it’s bottoming out on everything. Unfortunately, there are some bad tunes out there, but that’s not a knock against doing any mods on a daily!

    • 0 avatar

      “If you’re a car guy you get it”? What…someone who drives a Veloster N isn’t a car guy? We’re going to disagree there. Besides, how much faster does a Veloster N really need to be?

      • 0 avatar

        No, I meant that if you weren’t a car guy, you would buy a regular Kona over the Veloster N, because you would probably feel it was too loud, too low, too crashy, and too high strung in general.

        If you’re a car guy, you’d take the Veloster N any day of the week. I know, I own one! I’ve proudly overcome the PTSD I developed from fearfully dodging potholes through counseling and it’s really a great car.

        I have a modified E36 M3 with coilovers, cams, air intake, tune, exhaust, S50 manifold, short shifter, ZHP steering rack…it’s tuned like hell basically. I consider the Veloster N to be along the same lines. It’s pretty spicy from the factory. I don’t see myself modding that one. Actually, the N led me to do some of the mods on the E36, because it didn’t measure up in steering feel, for one example. So I did the ZHP rack.

  • avatar

    I get the point. I know that in the GMT900 circles models from 07 to 10 with the 5.3L advice number one for someone is to get a tune, defeat AFM, and crisp up the shift points. For 11-13 the advice is do it anyway.

    The AFM issues from 07-10 are well known (changes in 2011 were an improvement but frankly I’d still disable) and the shifting was set to be sooooooo soft and conservative to squeeze another 1/2 MPG out of the platform.

    To the mention of things being set conservatively. The G8 GT with the 6.0L V6 was extremely conservative from the factory. CAI, catback, and a tune would add 30 WHP and 20ish torque with no impact to the engine, transmission, or rear end life, or having to do more radical things like fooling the O2 sensors. Dollar per HP it was a bargain.

    On the other hand, for the argument against doing tunes. On the G8 GT those who did OTR intakes discovered that rainwater could intrude, soak the air filter, and hydraulic the engine.

    • 0 avatar

      I’d think the main argument against tuning a G8 GT can be searched on YouTube – “cars and coffee crash”. It’s real easy for a powerful RWD car with a big V8 to get away from someone who doesn’t know how to really drive one (and I’d include myself in that category – I sold Chevys in the early ’90s, and one day I took a Z28 out for a little lunchtime joyride, which ended with me getting sideways, and almost into a tree). This is probably why GM tuned the car conservatively.

      • 0 avatar

        If you can’t control the car, at least control yourself. A 140 HP ’78 Mustang II can get you in just as much trouble.

        Although it’s not that hard to learn. Mostly you have to unlearn (completely) letting up on the gas as soon as anything unexpected happens.

        • 0 avatar

          One day after I’d swapped in a locker to my 289 Mustang, I punched it in a rh turn from a stop. 2 seconds later I’m sideways in the rh ditch still going 40 with my nose pointed at the centerline.

    • 0 avatar

      I dropped any thought of modifying my G8 GXP (beyond a couple of Holden interior trim parts) the first time I saw a forum post about a hydrolocked L76.

      And that probably saved me a couple thousand when I sold it.

      • 0 avatar

        I had zero interest in the OTRs when saw the issues. I went with a Volant, did J-tubes in the back, and a Volant-specific tune on 87 Octane.

        Went back to stock before I sold the car. Need to sell those j-tubes thinking about it now – they’re taking up space in the garage.

  • avatar

    I’ve lived in my neighborhood long enough to see a lot of young people grow up and get their licenses. It’s only in the past year that a few of them added “performance” exhaust systems to their daily drivers and have blessed our quiet community with a holy racket. I swear, one car sounds like a chain saw.

  • avatar

    I don’t trust the engineering behind most engine tunes; I tend to think there’s a reason that the factory tuned the engine how it did, and that reason is most likely to be durability.

    I feel similarly about any modification that changes the suspension geometry.

    • 0 avatar

      I agree, I would never tune something unless it was not my DD and the tune/mod was proven or stable, i.e. as in the example given with the SLK and C350.

  • avatar

    Is this editorial specifically about tuning older vehicles, or also taking new cars and immediately tuning them? I could imagine there would be differences in the calculations, new versus old.

    Years ago I test drove a Mustang that was on the “gotta-have-it green registry”. The salesman talked about all the mods that had been done and mentioned the horsepower numbers. I confess that I forget since I thought overnight about it (the bank denying financing only helped – this was 2015 and the car was a 2007ish 6cylinder stock) and they were asking $15k iirc) and decided it wasn’t a good fit. The car was obviously taking a lot of abuse at the hands of the salespeople because of the “fun” or something.

    The exhaust was too loud and I presume it had had the snot beaten out of it.

    My friend bought a Focus ST in 2015, and immediately tuned it up, allegedly to something like 310hp. He got rid of it a year later after he realized the dealer add-ons pushed the price/monthly payment into stupid heights.

    I have my current car, the Mazda3 Turbo, and vaguely consider a cold air intake. However, I’m not necessarily looking to wring all of the possible performance out of it as possible. I admit that I like the noise. I primarily bought it so I can get up to speed and get out of dodge much more easily

  • avatar

    I understand “tuning” like bigger brakes, but I’ve owned enough tempermental clunkers to know that if a car works its best to just leave the mechanicals be and drive it.

    The best “mod” for your daily driver will always be a tune up and some fresh tires.

  • avatar

    I just got rid of a car because it had a temperamental engine that I was on the hook for repairs for, so there’s no way I’m modifying the car I traded it in on and voiding the warranty. The car’s plenty fast without mods.

    However, I am in the market for some interior trim adds, as long as they’re tasteful and blend well with the interior.

  • avatar

    Makes me wonder if the new owner of my old 2015 Audi S5 cab even notices the APR Stage 1. Or if the next owner of my current 2017 Audi TT cab will notice.

  • avatar

    BS. Any part that wears out is a chance to upgrade.
    Shocks ? Bilsteins-or the “sport version”…always an up there.
    Tires ? OE usually isn’t great, lots of room here.
    Brakes ? Better or bigger-when the pads wear out…

    We bought a 2017 Jetta S. No options, but the facelift car had the IRS and electric steering of the GLI. Tires and wheels…easy. Tires wear out, the wheels were a buy. Shocks and springs…TUV approved Bilstein Eibach kit. “the car drives like it was 30k more expensive”, says mama. Brakes ? Base to GTi brakes are super easy with junkyard parts. Now, the base S drives like a GTi….but for HP.

    I don’t expect to get the money back but half was normal upkeep.

    You can be sure the tune is next….but my VW scirocco turbo was tuned, my A2 GTi 16v had a “chip”, and I turn the screws on my Superjet twin carbs so what exactly does “tuned” mean, anyway ? Allowing a few extra pounds of boost messes with VW marketing at worst…

    Any enthusiast looks to tweak the car….sometimes the compromise is a company thing (cayman slower than 911) or cheapness (shocks on most OE fitments)…

  • avatar
    Avid Fan

    I’ll go one step further and say it’s irresponsible to tune your daily. I mean if you want to throw a chip or an air cleaner on it fine. FnF it till the cows come home. But if your over 18 and have friends and parents that may, in some universe, depend on you to get to the airport, doctor, grocery store etc it absolutely borders on being irresponsible. Aw, gee, sorry you missed your _____ but you gotta see the sweet stance I just rigged up. SLAAAP! Grow up and be an adult. Buy something that runs and drives and save your pizza and beer money for an honest to goodness track/hobby car that can sit on blocks for weeks at a time.

  • avatar

    After spending over 30 years working on cars I couldn’t agree more with this piece. I have seen so many nice cars ruined with cheap Chinese crap I lost count. I call the “tuner” kids (and they are always young and think they know more than they do) “Detuners.” Never forget when I was a service manager and a little punk brought in a crapped up GTI with a blown engine demanding a loaner vehicle immediately and expecting us to drop everything and fix his car. Had the technician pull the data to see that the last recorded RPM was 9,500+ and the boost pressure was way over stock. Told him next time he was speed shifting to make sure he hit third instead of first, as this was not a warrantable condition. Also told him since his car was obviously chipped I made sure to note it in the system and his remaining powertrain warranty was now null and void with VW. Asked him if he’d like us to quote him an engine or if he would like to tow it to the shop of his choice.

  • avatar
    Art Vandelay

    You just sort of have to understand what you are working with. I’d have no issue throwing a cam and tune at the LS in my C5 that I daily. It is understressed and 20 years of data shows it can make more power and be perfectly reliable. I’d feel the same if I had a Ford Modular motor, 2JZ, or any of the other known quantities in the performance world that have been around. Just use quality stuff and stick to the well known stuff for a daily.

    A car like my old Fiesta ST? Probably not. Smaller community with less data about the long term on modding it and a generally higher stressed motor.

    Anything still under warranty I won’t mess with.

  • avatar

    Given the example of a 10 year old,100k+ GTI or something similar, wouldn’t a fresh set of suspension rubber, tires, brakes and brake hoses take as much time or more off a lap as throwing a chip, intake and exhaust on an already tired motor? Most of the people tuning on a budget never even got to drive their cars showroom-fresh. You’re probably not going to out-engineer millions of dollars of R&D with the back page of JC Whitney.

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