As I guided the revised Boxster S onto the off-ramp at a not-inconsiderable speed, I instantly concluded that Porsche's engineers have switched from coffee to amphetamines. While the previous Boxster S would have sasheed through the ½ mile curve with sure-footed ease, the updated version wanted to chew up the tarmac and spit it out. The snarls and howls bouncing off the stone walls flanking the roadway left no doubt that the more "evolved" car likes living life on the edge. There was only one thing for it: go 'round again.

The second time through the corner, I held the Boxster S in second gear and mashed the gas. The car added speed like a boulder rolling downhill; the transition from bottom end torque shove to Variocam assisted accelerative thrust was as seamless and powerful as gravity itself. The Boxster's variable-ratio steering rack and [optional] 19" wheels responded to the smallest steering input with a fencer's speed, a surgeon's precision and a Rottweiler's tenacity. The resulting line through the ramp's radius wasn't pretty, but it was very, very quick. Oh yeah, and fun.

Sports car drivers are fetishists. Where a normal person looks at the new Porsche 911 Carrera's front end and sees a pair of headlights, an enthusiast instantly discovers that The Sultans of Stuttgart have ditched the "fried egg" shape of the previous 911's illumination, and returned to the old air-cooled car's circular headlamps. Porsche-philes will also clock the subtly reshaped nose, and the new, tidier headlight spritzers. It's sad, but the 911 does that to people. The Carrera is one of those rare machines that can turn a disinterested driver into a raving car nerd.

It's not about looks. The appeal of the 911's gently evolving design is more or less lost on the non-cognoscenti. There's no question that this, the latest 911 iteration, is more attractive than the one it replaces, even if it's difficult to identify the exact cause (the smart money is on the wasp-waisted flanks and purposeful rump). Still, as beautiful as it is, the revised shape is no radical departure, no newfound siren song to lure converts into the 911 fold. No; the essence of the Carrera's transformative powers lies behind the wheel.

Imagine you've driven 165mph in a Volkswagen Phaeton W12 on a derestricted German autobahn. Now imagine you're driving a Porsche Carrera GT (CGT) on a three-lane American highway with no traffic, one mile visibility and perfect weather. Do you put the hammer down and try to better your personal land speed record, despite the obvious risk to life and license? Do ya? Do ya punk?

Well, of course not. That kind of egocentric accelerative exuberance would be criminally irresponsible, regardless of the conditions. Anyway, your [imaginary] right foot rests atop an accelerator hot wired to a 605hp, race-bred, V10 engine. The car holstering this brute weighs just 3043lbs. It's a Porsche. So what the Hell, you muck about a bit, change gears, play around with the throttle, that kind of thing. I mean why not? It's not like you're headed for work or anything.

I have never driven a Porsche so slowly in my life. Of course, it was broken. Please note: it wasn't the company's fault. When the nice man from Porsche handed me the key to the Cayenne S, the box fresh SUV looked more than ready to show the world that the Sultans of Stuttgart can build a damn fast, fine-handling truck.

At first, the aesthetically challenged Cayenne S motored down the Spanish pavement with reasonable aplomb. That said, the coil spring suspension reminded me of a tightly sprung trampoline. But hey, not even the Germans can tie down an SUV to the point where it can blast around corners, without falling over or ploughing straight ahead, while providing Jaguar ride quality. The best thing that can be said about the Cayenne S' on-road comfort is that the BMW X5 4.6 Sport is a lot worse.

My last review of a Porsche was more of a love letter than a critique. For that, I make no apologies. The warp speed 911 Turbo is the best thing to come out of Germany since apple strudel. However, in the interests of perceived objectivity, I will resist the urge to shower the 'new' Boxster S with praise. Suffice it to say, the Boxster S is one of the finest driver's cars in the world, at any price.

Kirk Stingle, my favourite Porsche salesman, describes the 911 as the 'Swiss Army knife of sports cars'. It can cruise, thrash, potter, pose, park and ferry in all weathers, with equal aplomb. Get jiggy with the options list, and you'll enjoy all the latest luxury car toys and creature comforts. At the end of the financial year, a fully specced, top-of-the-range 911 is still cheaper than an 'entry level' Ferrari. Other than a winning lottery ticket, what more could you want?

Power. And so, on the seventh day, the zealots of Zuffenhausen created the 911 Turbo. And on the eighth day, they created the Power Pack. These factory enhancements increase the engine's peak output from a not inconsiderable 420bhp, to a monumental 450bhp. The zero to sixty time sinks to 3.79 seconds. Porsche calls the extra oomph an 'option', but c'mon, you know it isn't. Put it this way…

This is a tale of two Carreras. The first one is Muhammad Ali. This Porsche floats like a butterfly and stings like a bee; it can motor at extra-legal velocities with no apparent effort, then carve-up a twisting road and leave it for dead. Muhammad is flash, a smug symbol that its driver is a Heavyweight. But it's no bum. Oh no. Press the loud pedal and the 3.6 litre engine proclaims, 'I am the greatest!' As the roar increases and the scenery begins to blur, the car gains control rather than loses it. The footwork is dazzling. Class. Pure class.

The second Carrera is Clint Eastwood. This Porsche upholds The Law of The Jungle, with scant regard for legal niceties like speed limits and other road users. In fact, there's nothing nice about it. Clint sticks your nose into the tarmac and makes you feel every bump, ridge and rut. As far as speed is concerned, the bullet chamber is always loaded, the hammer cocked. Pull the trigger and Clint explodes into forward motion. Cornering is equally brutal, and effective. Calling this Carrera 'soft' or 'not as good as the old one' only reveals your ignorance.

The snow falling from the leaden sky over Pffanhausen made me nervous. As did the fact that Natalie Campagna, Keeper of the Keys for RUF Automobile De, couldn't look me in the eye. And no wonder: Alois Ruf himself had just called to forbid the English journalist from driving the R-Turbo. On the face of it, it was an entirely sensible decision. Five hundred and twenty horsepower and drifting snow are not the ideal combination for a test drive- especially when the car in question belongs to a customer.

Plan B involved a ride in the passenger seat with a RUF technician at the helm, followed by a 'small spin behind the wheels.' As I helped push the immaculate R-Turbo out of the showroom, I hoped something had been lost in the translation. I took comfort in the fact that RUF's official press car- a yellow, rear-wheel-drive machine-was busy making sushi out of lesser cars in Japan. This silver car had four-wheel-drive and stability control. Oh, that's all right then… isn't it?

Are you a poser or a purist? Be honest. Provided you don't crash into a parked car while clocking yourself in a shop window, there's nothing wrong with buying a sports car to flatter your ego. But if you're more concerned about perception than performance, the RUF 3400S is not for you. It's a Porsche Boxster. Yes, RUF have modified this particular version to blast from zero to sixty in well under six seconds and out-corner a Ferrari, but it's still a hairdresser's car. Compared to the fearsome 911, the Boxster has about as much street cred as a dark blue M&S suit.

Ah, but if you are a purist, get ready for a treat. You'll already know the Boxster has one-up on its 911 stable mate: a mid-engine layout. (For the blissfully ignorant, the 911's engine sits behind the rear wheels. During heavy cornering, the car must use clever tricks to stop the rear end from saying, 'Wait a minute. Wait a minute. I'm the leader.') What purists can't know- at least until they drive the 3400S- is the Boxster's true magnificence. The official Porsche product just doesn't have enough power to exploit the Boxster's dynamic capabilities. In other words, it's too damn slow.