Increase horsepower in your WRX/STI and get a release an aggressive sound with this Cat Back Exhaust by Racecomp Engineering. This exhaust system was created with 3" 304SS tubing for maximum exhaust flow and longevity. Designed to directly bolt on to the factory down pipe, this cat back features a V-band connection that allows for tuning of the exhaust alignment and a "Y" section that splits the exhaust.