Like their sedan exhaust, the AP hatchback exhaust features full stainless steel 3" piping, but exits one single titanium muffler. This system is fully TIG welded and hand polished for a mirror finish. The system uses a resonator to keep exhaust drone at a minimum for an enjoyable ride. It has produced 17whp and 28tq on the 08 WRX hatchback. All hardware and gaskets are included.