You will NEVER pay for the diesel upgrade on that small of a mileage difference alone. The higher cost of diesel fuel and increased maintenance will eat the small increase in mileage. Of course, a diesel pulls better and will theoretically last longer (but the rest of the truck won't). You may make the some of the money back on the diesel when you sell it.
Premium gas is higher than Diesel around here. I dont see the 6.4 Hemi running too well on the cheap stuff. I'd say fuel cost is a wash...Quite a bit more intial investment for the truck, though.
A friend got the new 1500 Diesel, gets about 26 ont the open highway, that truck is pretty cool. Seems that may be the way to go to have a Diesel pay you back...
