The HKS Hi Power exhaust is arguably the best sounding catback exhaust for the boxer engine in the Subaru WRX and STi. Designed with huge 75mm piping, this stainless steel exhaust has a HKS Hi Power muffler featuring straight through design and a 120mm tip. More power through less bends is the philisophy, and HKS designed this exhaust to be as straight as possible to create the best power production from a catback exhaust. This straight design is what gives the exhaust the angled look. Due to the exhaust having less bends, it exits out of the back at an angle.