EXCEPT Vehicles With AEV Package. 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 Silverado 1500 ZR2 and Sierra 1500 AT4X and delivers great sound without any drone. Muffler contains an internal H-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. All this without the annoying drone often associated with performance exhaust systems. 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.