I have one on my truck right now. I replaced my broken banks muffler with it. So i am running 3 inch all the way. It is very loud in hard acceleration but not to bad when cruising the highway.
I am running one of these with a turn down i like the sound it doesnt sound like your everyday flowmaster. only thing it isnt loud enough for me so im going to upgrade to a 3" catback probably either jba or bassani depending on the bassani's sound. im not worrying about performance as much anymore now that i am lifted