.My last truck was an '07 3500 mega cab srw, new truck is a '13 3500 mega cab drw, both tow no problems, but the drw feels more stable in heavy winds, both were short beds, duh, i don't think dodge makes a mega cab long bed truck, as others have pointed out rear end ratio will change tow rating as will std or auto trans, and the new asin tranny gives a higher torque rating, i found.a.leftover 2013 and bought it for a substantial savings compared to the same.model in the 2104 and 2015 line up, not a lot of choices because it was a leftover, but very happy so far with the 2013. Excellent tow vehicle, no clearance problems anywhere, even with factory tailgate either on both trucks. 6.7 cummins, asin trans 4.10 rear end, is a beast, the 07 had tuner, intake and exhaust done so had a little more power, better mileage as well, working on that now with the 2013, installed a new cold air intake, picked up 3 mpg alone, tuner is next, chose another edge juice with cs, same as the 07 had, should pick up another 3 mpg, not sure on exhaust yet, did 5 inch dpf back before, may do the same again. Anyway you can't go wrong with either choice as both srw or drw are more than capable of towing your new fw.