Invidia's Racing catback exhaust for the WRX & STI feature 3" stainless steel piping with no resonator for optimal flow. The the N1 muffler has a JDM look and either a 4" burnt titanium or polished stainless tip. This system is louder than the G200 and Regular N1 catbacks - it is exceptionally free-flowing but very loud. the included silencer helps to significantly reduce noise, but this is still a loud exhaust.