400+ wheel hp? you could leave the internals alone, and it would be really fast, until you bend a rod and trash your motor.you'll need to blow 15+ psi to make it happen, and for that you'll need rods and pistons, something in the zone of 8.5-1 compression so the turbo can fill the cylinder with the massive amount of mix you need for that power. the stock duration for cams should be fine, but get something with just a little more lift to maximize your power. a quality turbo kit should come with fuel management and software, so you'll have that covered. i'm sure you already know you'll need a badass clutch and cv shafts. better brakes couldn't hurt, either.