Standard exhaust systems are often very restrictive. HKS, Japspeed, Blitz and Greddy exhaust systems are all designed to remove this exhaust restriction. Increasing the amount of exhaust gas flow is the first step towards increasing engine performance and efficiency. Aftermarket exhaust systems are designed to help your engine breathe more easily by increasing the mass and velocity of exhaust gas flow. Thus allowing for a reduction in back pressure and thermal stress and unleashing engines potential for increased power, torque and response.