The Borla catback exhaust for the WRX/STI hatchback is a full stainless steel exhaust system that uses slip fittings for easy install and removal. The piping tapers to 2.5" right before connecting to the downpipe for great fitment using stock or aftermarket downpipes. This system does not have any resonators and will be fairly loud, but not overly noisy and annoying. It will however net you some serious gains throughout the power band and improve throttle response. The construction of this exhaust is second to none and as with any Borla product, they offer their million mile warranty. You can be sure you will not be replacing this system anytime soon.