I can help out with specs, make rpm/mph charts, etc..
Nowadays the wrong specs can cost you 20k a year, easy.
Something as simple as a direct drive vs overdrive, the direct drive tranny can save you 2k a year!
If I was buying a new truck, it would have 2.64 gears, super singles OR XDA "energy" low pro 22.5's, a 10 speed direct drive ultrashift, or maybe volvos I-shift if I was going with a volvo engine.
I talked to a guy running that combo, 12 speed volvo direct drive tranny, and a 485 D13, he said he was getting 7.5 mpg at 60 mph. Almost unheard of with a new 2008 truck!
Anyone that buys a non-aero truck nowadays is nuts.