It sounded the same not dumped, only less loud. No fart sound EVER from a Dynomax. The "roving fiberglass" they use just roves around the muffler, and doesn't seem to come out, lol. They way they retain it is different than in the old style "glass packs" you're thinking of.
As I think I mentioned, it's not much louder than stock, just much deeper.
I think it would sound even better with the dual outlets, but I've never heard one of those in anything but other brands.