Invidia's downpipe is a great way to start adding Horse Power and Torque. This system was tested in Turbo Magazine, they found that when combined with the cat-back section, HP gains were seen up to 60+ at the wheels with engine management.
The downpipe is constructed of 304 stainless steel with a large bell mouth, which will ensure longevity while enhancing power by freeing exhaust flow. 3" mandrel bent and bolts up to any stock replacement catback or stock unit. This downpipe also has an extra oxygen sensor bung welded in so you can install a wideband oxygen sensor and keep the stock one intact. It comes with a plug installed so you don't have to worry about not having one.
Invidia Gemini (R400) Single Layer Quad Tip Catback Exhaust - Titanium Tips - 15-20 WRX/STI
If you're in the business of adding artwork, sound, performance, and value to your vehicle, then you will be pleased with the Invidia Gemini Titanium Tip Cat-Back Exhaust System. This exhaust system...