The Agency Power downpipe is full stainless steel with a cast bell mouth upper section. The thick flanges ensure a tight and strong seal. The downpipe deletes both your catalytic converters and bolts to all factory style turbos. The downpipes precision welds and polished piping give the AP Racing Downpipe that cutting edge. Each downpipe includes a bung for an aftermarket air/fuel sensor as well as a bung for the factory O2 sensor. When adding an Agency Power Racing Downpipe to your Subaru WRX or STI, you will gain more horsepower and overall performance. The downpipe allows for better flow of the turbine and wastegate gasses. Unlike the factor downpipe that blocks the wastegate gasses from being released in an efficient manner, the AP downpipe has a large bell mouth which allows for both to flow smoothly out and down the pipe. The 3 inch diameter piping is the perfect size for the turbo cars from stock hp to 500 whp. The bellmouth will also allow for a little boost increase since there is less restriction. Mate this downpipe up with the Agency Power catback for an amazing sound and almost 25 wheel horsepower gain.
