I have a 4" stainless MagnaFlow. They have two different systems out: a fully polished 4" with a 5" tip for roughly 800 bucks and a non-polished system with no tip for roughly half that. I ordered the cheaper system and added my own tip (5"x24" polished MagnaFlow). I have run nothing but straight pipe on all my previous Dodges, but the 3G's don't have the same sound. I am extremely happy with the MagnaFlow. It's quiet at idle, sounds just right when cruising with no drone, and noticably loud when you stomp on it.
Hope this helps you out in your decision.