I've not read any of the thread, however a muffler thread does come up from time to time on the Deuce. I put a big Donaldson 3 inch in and out on my truck, cut the pipes so stack height would be same as stock and rotated to go perpendicular to the cab. Very good difference at idle, slight improvement driving under throttle, and I can still clearly hear the whistle from the C turbo. I originally had a D turbo when I put a muffler on, I prefer the whistle. Honestly though, the C turbo helped to quiet down the drone, perhaps by breaking up some of the lower sounds. And the wife can still hear it from a mile a way when I'm coming home.