I did an experiment a few years back with a new truck purchase. In 2008 dodge was offering a lifetime powertrain warranty on the 1500's but not on the 2500's and up so we bought an '08 ram 1500 regular cab shortbed 4x4 with the 310hp 4.7, auto, towing package 4x4 etc for over $10,000 less than a comparable 2500-3500 with the hemi and hooked it up to a 20ft carmate (heavy) enclosed trailer with 2 60 inch ztr's and all associated small equipment/tools. Trailer was loaded properly and the truck had a top quality brake controller, rear helpers, and a curtis plow frame out front that added some weight to the steer tires. That thing towed beautifully for 60,000 miles (not all towing) and plowed in the winter with a heavy duty curtis 7.5ft plow. Replaced both tie rod ends and the original brake pads at around 50,000. Engine, trans, transfer case, rears, ball joints all were perfect. I still can't believe how well the thing held up. Traded it in far around $5000 less than the original purchase price last fall because values were so low when we bought and skyrocketed last year.
If I could do it again I would...
That said we have a couple cummins trucks and a 7.3 ford and have switched to buying used 3/4 and 1 ton trucks for less depreciation