Re: what should I buy
80% of F HD series trucks have towed, be it a seadoo to a fifth wheel. I'd get the one with the lowest overall mileage. Diesels are pullers. If it was a gas engine I'd say forget it if the mileage was over 80K. With the diesels as long as mileage isn't too high, and the price is right I'd go for it. If you can be sure to get any or all previous maintenance records as well, this will let you know that the owner has kept the vehicle properly maintained.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!