Buying lightest possible system is the way to go if you're racing. For a daily driver, you have to like the sound and price. The ARK Grip is 100% 304 stainless and will outlast the human race. Don't know the composition of the others but something to think about.

 

Doesn't Stillen specifically state that their exhaust hp gains are assuming the car has been tuned and used in conjunction with other mods? i.e. their CAI?