Every Gibson Header is Dyno-tuned and engineered to deliver more usable horsepower and torque at low and mid-range RPM highway speeds. Improves engine's 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.