For Subaru WRX and STI sedan owners looking for a complete free-flowing exhaust solution that runs from the turbo all the way to the bumper; this is it. The Turbo XS quad tip turboback exhaust starts with a 4" bellmouth downpipe, tapering to 3" and bolting into a 3" high-flow catalyst or 3" race pipe, then into a 3" midpipe, and ending in a quad tip muffler with burnt titanium tips making a complete post-turbo exhaust solution. The large piping diameter on the Turbo XS catback make it one of the best at adding power on the market.