I think the sound of my old 6.5 turbo diesel is almost perfect....My son in law drives it now. My Duramax is kind of loud but it's chipped and it is still kind of thrilling to jump in it on occasion. I neverliked the noise pollution comming out of my old 5.9 Cummins diesels and so I've got an old Ram with under 100,000 miles on it that probably hasn't been started in over 10 years. When I really want to feel like a trucker I can run the Cat C 15 in my Peterbilt or if I prefer a quiet smooth ride I take the Cummins ISX 15 equipped Kenworth. But of all my trucks I think there is no time like heading down the highway in my Ford with my woman on my right and my fiver on behind.