The Turbo XS Stealthback exhaust is designed for the WRX owner that want keep their stock muffler, or want to use a different axle-back exhaust. The TurboXS Stealthback exhaust system has a free flowing 4 inch TurboXs bellmouth downpipe, which tapers to 3 inch at the end. With the TurboXs stealthback exhaust you can choose from either a 3 inch High-flow catalytic converter or a catless racepipe. The TurboXS's cat to downpipe connection features an OEM style ball-and-socket design with a donut gasket. This allows exhaust movement while maintaining a tight seal. From there it goes into a full 3 inch midpipe that has a unique rear flange that will either allow you to install a stock-type 2.5" diameter muffler, or a full 3 inch rear muffler.