Cobb's new system is constructed entirely of high-quality T304 Stainless Steel, from the hangers to the flanges. The COBB WRX Cat Back Exhaust system replaces everything after the stock catalytic converter with smooth, 3" mandrel bent piping. The system is tastefully finished out with a specially designed, robotically welded Stainless Steel Muffler directing the exhaust gases out a double-walled 3.5" tip featuring an embossed COBB logo. The results are improved performance and a nice, sporty sound – not obnoxious or buzzy. 100% Emissions Legal and Subaru Warranty Friendly.