Downpipe Kit with 200CPSI Racing catalyst for BMW M2/M3/M4 F80/82/83/87 made out of high quality stainless steel 1.4301 (SS304) complete Ø3 Inch and adapter for stock exhaust Racing Metal Catalytic Converter (200CPSI with high quality EURO 6 coating) 100% perfect fit, replace OEM less thermal load on the turbocharger more power by reducing back pressure significantly more torque