So you can fit a decent diameter tire in the wheel well. Even after relocating the axle back it's still very restrictive unless you like the jacked up rear look.
I know that leaf spring Mopars weren't prone to wheel hop because they had such a short leaf section in front of the axle. Will the movement cause problems if you're going to drag race it?
That's one of the reasons that I didn't do this one mine. I'm guessing you're losing the "Mopar leaf benefit" but I guess you can run Lakewood bars like the other guys then.
This is not a straight answer... It depends on a variety of factors. If you keep the same rear, probably unless the DS was very tight. If you do this mod and go from a 8.75 to a dana, no. Now, more trouble. If you go to a dana and run a performance cover you will have to do a little grinding on the cast rib. and you may have to dent or modify your tank.
The next thing to address the OP is the shocks are not an issue. They still get hooked up stock. 1.5" isn't much at all. You'll see that. Don't' move your rear shackles either. I assumed you need to. You don't.