Well I've heard various opinions on it, but you "can't run true duals". Most of the rednecks around where I live run their Chevy's and F-150's with single in/dual out mufflers, which is completely different from having TRUE DUALS run. Just aggravates me for some reason...
I'm interesting in having single in dual out muffler run eventually, but it's not to high on the to do list. It's merely for sound purposes.