Part# 140075 is the more Aggressive "S-Type" Cat-Back(tm). The mellow "Touring" Cat-Back(tm) exhaust is part# 140053 Borla(r) Performance once again leads the industry with a high flow performance exhaust for the hot Subaru WRX and WRX STI. This Cat-Back(tm) system Borla(r) #140075 is custom designed by Borla(r) engineers for the 2.5L turbocharged 4-cylinder engine with automatic and manual transmissions. Winning on racetracks around the world has given Borla(r) a leg up on the competition with trickle down technology from the world's fastest cars. The unique design is a direct bolt-on fit that meets all emission requirements. The system has shown significant flow and performance improvements by virtue of Borla(r) XR-1 patented technology utilizing 3" tubing that exits with a super looking Borla(r) logo embossed 4"angle cut rolled edge single round polished T-304 stainless steel tip. More flow means more power and if you tune this turbocharged super import that flow will simply allow even more power. When you get a close look inside this muffler you can see the patented Borla(r) XR-1 multi cores -- that look says total performance. Increased fuel mileage is an added benefit. And one more thing it has a great sound too but then you've come to expect that from Borla(r). Add a Borla(r) header (#17217) for even more performance. Borla(r) Performance Industries the original pioneers of high quality T-304 austenitic stainless steel (superior to T-409 or aluminized steel) free flow exhaust utilizes its patented award and race winning technology to deliver quality sound performance gains and enhanced fuel economy all with an easy bolt-on installation. All Borla(r) street products carry the famous Borla(r) written million-mile warranty.