They are slightly louder but have a deeper, nicer tone. They don't rap at all like the stock manifolds will. I have a magnaflow muffler on my truck so it's not super loud to begin with but it sounds a lot better now. They gave my old Dakota a nice snarl when I had them on there but that had a 2 1/4 y pipe, no cat and a thrush welded muffler on it. That truck was LOUD.