Just to muddy the waters some more, it's not always just the muffler that makes the exhaust sound different.
I have a set of Walker Turbo mufflers (from NAPA) on my Challenger, with headers, 2-inch pipe, and no cross-over. It is reasonably quiet idling but does have nice rap when I put my foot in it on the highway. I used the same mufflers on my bird only with long branch manifolds, a cross-over and 2-1/2-inch pipe. And to me it's way too loud and has a very annoying drone on the highway. Much louder than my Challenger.