Didn't fit my STOCK header properly. cut and weld to fit it. After they fixed it to fit properly the standard sound is a lot quieter than I expected but I've also gone from a bunch of bad cats to a bunch of brand new ones, overall it seems to be a decent quality and build, but it doesn't fit my exhaust manifold after I got off so bad they actually had to cut it at the Y-pipe on the manifolds and then re-weld the new pipe to fit where there are no gaps where there is does not fit, something I could do at home alone, thank god I went to the store