This Borla(r) system has a valve simulator to prevent the Check Engine Light from coming on. It was designed specifically for the 6.2L Silverado ZR2 and Sierra AT4X. This Cat-Back(tm) system features the classic Borla(r) "S-Type" sound level and 2.75" turn down tail pipes. It features a True Dual design which is unique in the industry. Installation REQUIRES cutting the factory Y-Pipe. It was designed specifically for the 6.2L Silverado ZR2 and Sierra AT4X and delivers great sound without any drone. Muffler contains an internal X-Pipe for increased performance and improved sound. It is built with premium high-quality austenitic T-304 stainless steel using computer numerical control (CNC) manufacturing techniques that ensures accurate fit and maximum performance. Give your ZR2 or AT4X the sound it deserves bolt on a Borla(r). Best of all Borla(r) stands behind every system with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.