Every gibson Header is Dyno-tuned and engineered to deliver more usable horsepower and torque at low and mid-range RPM highway speeds Improves engineAs ability to breathe and cooler operating engine temperature Designed as a direct replacement for the factory manifolds, using the stock crossover pipe They are well suited for lowered and raised vehicles, street and off-road 50 State Street legal Meets EPA and cARB requirements Will not affect the factory warranty