Our Decat Downpipe compatible with the Subaru replaces the standard restrictive downpipe and catalytic converter with a stainless steel, 3" one-piece item. Increasing the bore of the downpipe and replacing the restrictive catalytic converter allows the exhaust gasses to flow much more freely, increasing the power output of the engine. Features: Manufactured from T304 stainless steel 3" bore all the way through TIG welded, CNC machined flanges Boss fitted to accept O2 (lambda) sensors Compatible with OEM and aftermarket cat back exhaust systems Gaskets included