well the only reason i wouldn't go cummins is the shear size and weight. the only reason i wouldn't go duramax is i just never liked duramax and the wright. they both have downfalls and they both have good too. but one over the other would be cummins for me but personally i think there is still alot to be had with an 8.1 but if it ever got in the mud it might not perform as well as a small block. i guess the difinitive factor would have to be $$$ whenever i got to that point. if i could find a 3500 chevy with a trashed body i would probably just run whatever motor it had in it to begin with. which would probably be a cummins. if i found a dodge 3500 it would probably have a cummins. and i really doubt i would tow with it anyway. really just not economical. but would be interesting to see. but its not like theres a good place to put a gooseneck in the car so i dont need crazy towing ability