HKS Sport Exhaust Catback | 2003-2007 Mitsubishi Evo 8/9 (31013-BM001)31013 BM001 2003 2007 Mitsubishi Evo 8 9 Sport Exhaust Catback by HKS HKS's Sport Exhaust Systems are designed to reduce backpressure and increase exhaust flow for greater peak power and a broader torque band. Each Sport Exhaust application utilizes a specific muffler design and shape along with the appropriate piping diameter to maintain low end torque while maximizing high end horsepower. Features Constructed from High Quality Materials Benefits