I have and 05 Eddie V8 and i went with a Magnaflow Part #12286, its the same muffler they use in their cat-back system. I love the sound, it mellow and not obnoxious, but when you get on it it comes to life.
EDIT* It drones a little between 1700-2000RPM, which is where most driving takes place around the city and then at cruising around 70MPH. I heard that after 1K miles it should quiet down a little, but I',m over 3k driven now and its still there.
have to redo the system anyway, there is a leak and a few broken hangers. Picked up a 2.5" 304 stainless tube and will add a long glasspack in front of the muffler, I have 3 exhaust guys telling me that will take care of the drone. Anyone want to chime in before I jump?