I think squat will eventually chime in on this, but I believe youre pretty much right. The 2500 might have the 4.10 axle ratio or something though as the only difference. But I'm guessing he doesn't need it for hauling if he's lookin at a gasser in the 2500.
The
only difference between the 1500 mega and 2500 mega is the overload springs. The 1500 has only 1, the 2500 has 2 (or 3). You could get air bags to make up the difference. For a truck that heavy your friend should be looking at the cummins. The hemi would be a tad sluggish in an 8k lb truck.
You're correct about the differences. But I don't know about the hemi as sluggish in the megacab. I've owned 2 '06 Ram quad cabs with the hemi/MDS and my megacab is faster than those two were off the line. It may get 1-2 mpg worse and isn't rated to tow as much (dumb since it has the heavy duty frame) but it's got more punch.
I have no idea why this is. My only guess would be that the MDS hemi's have a program that runs and does 23543589439543 calculations when the throttle is hit to see if it can either stay in 4 cyl. mode or move to 4 cyl. mode. The megacab wouldn't be as hindered in that respect.