Matt, from my experience with a one muffler system:
One muffler in the middle will still sound bad*ss. It's honestly not raspy...at least not raspy like the res-less 'tours are.
Drone isn't too bad. You'll certainly hear the exhaust, but that's good.
Lower the rear seats, and you'll hear some more drone on the highway. I could dig up some (way too short) sound clips of a one-muffler system if you like.
BTW - go with something straight through for best flow (i.e. dynomax, magnaflow, or edlebrock). Guaranteed good sound from any of these choices, too.
