I have a 08 Ford F-450, will not pas a fuel stop, also have new 08 Duramax 3500HD. Love it, more power and gets twice the milage.

His truck is broken in, about 20K miles now. 6.7 and 6 speed auto is a great combo, the 5.9 and pos 4 speed sucked, which is why he got the 6 speed manual instead. Truck only seems to get 16 on the high way empty, his 5.9 that was lifted on 35's with performance mods would get 21 highway when we'd go dirtbike racing.

If anything I'd get an 05/06 6.0 Ford, this new emissions crap sucks. And seems the ones trying mods or playing around with the new motors are having issues.

with the performance mods you will gain a few mpg over stock. If you keep the power mod at a sensible level the new diesels are fine if you go over the barrier, you will have issues just like the old ones.