well I have had 2 diesels so far. my first one was a 02 F250 7.3 powerstoke, it had two 6 inch miter cut stacks and a dp 16 position chip on it and that was it. I was 16 when I got it(I am 18 now), I loved the way it sounded it had to be the loudest thing I have ever heard I loved that thing but a few weeks ago I traded my powerstroke for an 06 gmc duramax lbz with only 73000 miles so far I have efi live, 5 inch turbo back, S&B cold air intake, shim kit, and a lift pump. I would have to say that the duramax has the most power It has a little more then 500 rwhp on my powerstroke I am guessing it had something around 350 to 400. overall I think that the duramax is better.