Well I finally got a duramax. And all I can say is wow. I got an 02 3500 crew 4x4 and it is amazing how nice it rides and how it gets up and goes quite nicely. I looking forward to tinkering with it and getting more fuel mileage. I check it for the first time and got 17.5 mpg. Dam, i only got that with my cummins if I drove like a granny. I would like to do an exhaust, what is a good muffler that has a good mellow sound but is free flowing? Thanks for any help and tips.