The Cobb Tuning Mitsubishi Evo X “Test Pipe” features a high-flow catalytic converter and is a direct bolt-in replacement for the restrictive factory unit. Made of 304 stainless steel with a 3″ diameter, Cobb?s Test Pipe will work with the OEM exhaust, as well as any exhaust that is designed to keep the factory catalytic converter. Reduce back pressure in your exhaust and free up horsepower with this easy to install mod.