The COBB Tuning Turboback is the ultimate power bundle for your 2015+ Subaru STI! Simple plug-in and bolt-on installation of these components offer excellent power gains, outstanding build quality and an impressive exhaust note. The Turboback includes: COBB 3" SS Downpipe - Cast bellmouth and high-flow catalytic converter for optimal exhaust flow COBB 3" SS Quad-Tip Cat-Back Exhaust - Beautiful fabrication and awesome rumble