I think this is one of the Loudest chambered Setups ever

Mine sounds just like that, and my car came with flows (don't know what kind) and I just installed the H, it's not really that loud. At idle and around town I don't find it that loud at all, although my dad who grew up in the muscle car era says it's pretty loud, but when I open it up it's a whole other ballgame. That and the tone is also awesome.
 
i Think mine is a little louder. 3 in. X pipe with 2 chamber flows. They might be hollowed out i'm not sure. The set up was on my car when i bought it. My friend was sailing about a half a mile out and herd my car...i'll post a clip when i put it back together.