Cobb Tuning's 02-07 WRX & STI catted downpipe uses a 3" bellmouth that scales to the stock 2.5" size piping where it connects to the mid-pipe. The Cobb downpipe is designed to bolt to any stock or 3" aftermarket catback exhaust.
A factory style donut gasket attaches this downpipe to your catback. All Cobb WRX & STI downpipes feature a unique, cast bell-mouth and an oxygen sensor bung close to the turbo that will come in handy when you want to run your 02-07 WRX or STI on a dyno.
