Steve here is the issue with d max pricing.
The engine will run about 5K as an option, and then if you want the allison tranny, that will add about 2500 to the truck, all on top of the other options you are loading the truck with. The diesel will get 2x the mileage of the gas engine, so if fuel prices are= for gas and diesel, the break even mileage vs extra money for diesel option will be in the 75000K range. So if you plan to keep the truck longer than that, then you will benifit. Of course actual fuel prices will vary the outcome. I based this on 20 mpg for the diesel and 10 mpg for the gas, and pump price of 1.75 per gallon. That is about what we pay for fuel here in CT. That also reflects that i the summer diesel is a little less, and in the winter a little more. Right now they are with in $ .03 of each other.
I am not the biggest and I am not the best but I fall somewhere comfortably in between.