Okay guys, trying to figure out something. I have a Corsa Sport muffler on my truck right now. Inside the cab it sounds great. Idle sounds like a typical Corsa. But I noticed when someone drives it past me, or when I have my windows down it sounds like an angry motor boat - very gurgly and muffled sort of. I've had Corsa on vettes and it sounds great outside too. Even watching some youtube videos mine doesn't quite sound like other 5.3s

The muffler I picked up off a guy with a Tahoe that had the whole sport system, but stepped up to a Borla muffler. The muffler got welded in place of the stock muffler, factory y-pipe, correct orientation, drain hole down and new 3" inch pipe all the way back to a single tip.

Any reason why the sound isn't what it should be?