Your rear end sag will not change from what it sags currently. So if you sag with what ever you haul say 1" then once leveled you will sag 1" but after leveled you would look noise high so for the best all around results you will want to add a set of helper air bags to maintain the same before and after ride height in the rear . Another option is to add a 1" rear block and ubolt kit but of course now you will not have a leveled stance after everything installed, you will be 1" higher in the rear and why I would suggest the helper air bag investment... much better way over all.
Would I be able to fit 35's with mudflaps with a 2 inch lift in the front
and a 1.5 in the rear? I have the shock extenders and torsion keys but I
have heard it is a bad idea to install them.
is it a 2500? or just a 1500? u can fit 35's with just a leveling kit but torsion bars gotta be cranked a ton and u gotta trim alot of metal and plastics cause it will rub alot also. but installing keys isnt bad and shock extenders are ok