The complete kit from the Y-pipe to the muffler fits the Sierra from 2007 to 2018. The kit is Max Power, complete, and the muffler is an original part. It has a Bullet muffler installed, and I replaced the muffler with a Max Power double-silencer muffler, which has no backpressure and its sound is original. The muffler was not installed, so there was no backfiring or overheating. You only need to weld it to the kit. The price is 2500, and we can negotiate with serious buyers. Location: Hail