Mishimoto's Performance Downpipe (J-Pipe and I-Pipe in one)for the 2015+ Subaru WRX. The biggest restriction in the stock exhaust system are teh factory cats in the stock downpipe. By installing the Mishimoto Performance stainless steel downpipe, the FA20-DIT exhaust system is able to breathe easier, providing a significant increase in horsepower and torque when tuned. The Mishimoto Performance Downpipe provided an extremely aggressive turbo and exhaust tone under acceleration and boost, giving you that aggressive tone you have been looking for!
Mishimoto offers both a completely cattless version of their down pipe, which deletes both factory cats (and the factory resonator) as well as a version with one cat in line. Which ever version you choose be aware that you will need to have your 2015 WRX tuned to make use of the freed up airflow and the lack of catalytic converters. If you do not get a proper tune you will have check engine lights and likely will go into limp mode. Get you car tuned as soon as you have this part installed.