When car companies need to stretch out a model’s useful lifespan, there are a number of tricks they use. After the first year, new colors are added. The next few year options and trim parts are tweaked. Around year four, a limited edition surfaces followed by a drivetrain revamp in year 5. And so it is with Infiniti’s sporty FX crossover, now entering its fifth model year as the “new” 2013 Infiniti FX37. You guessed it, the only thing new about the FX37 is the engine. Today’s burning question is: does a new engine give a luxury vehicle a lease on life? Or is this thinly disguised crossover life support? Click through the jump to find out.