x2 on that part. Plus with the optional upgrades you can get some serious ponies out of the cummins. One of these days

 

Yeah they can make some ponies. I was told to look for an 06-07 5.9 since they can run EFI live, I guess that's the the best programmer out there, heard good things from Duramax owners. One of these days is right, hopefully end of the summer if I get an internship.

 

Anyone who tells you there getting 16 can't do simple math, my 5.3 was only getting 14-15 and my brothers 6.0 was way worse. They do have good power though.

 

I bet 16 is easily possible, mostly depends on driving habits and setup. I've seen 350s in 3/4 tons getting 18. I doubt that gms replacement for the 350 would get much less. With 3.73 or higher gears, I'd say that 16 would be no problem on a long trip. About 12-14 mixed would be a fair guess. But if they have 4.10s then you'd see 14 and less. But definitely not diesel mpgs.