Two Pickups with more similarities, such as the body structure, ground shadow size, height, and maximum occupancy, than differences, like the starting price and horsepower. First of all, there is a $4,105 difference in the base MSRP. The 2016 Ram 2500 Mega Cab has a higher starting price than the 2016 GMC Sierra 2500HD Crew Cab. And finally, the 2016 2500 Mega Cab pulls more horsepower than the 2016 Sierra 2500HD Crew Cab. Among similarities are the body structure, ground shadow size, height, and maximum occupancy.