Let your STi breathe better with a performance downpipe from Injen Technology. Mandrel bent full three-inch stainless steel, these quality Injen downpipes feature thick flanges and a cast divided-wastegate (aka divorced style) mouth at the turbo connection. Unlike most other downpipes on the market, Injen has welded an 02 sensor extension on to their downpipes from the factory, minimizing your chance of seeing that pesky check engine light. A downpipe is arguably the most effective modification you can do to your Subaru so why compromise? This downpipe is fully catless and is recommended for track use.