What will a predator tuner do to a stock car or one with just a K&N and exhaust system? What's the best model to get? Can you screw it up and will it show up on the computer history if you need warranty service? Have been reading up on them but prefer the cheapest gas I can run without listening to then engine complain like an ex wife. Why did you purchase a predator or like tuber and how much will they evolve in coming times?