So, dont know if you've made and decisions or changes yet but here's my experience with the rear.
I kinda had the same issue. Rear always looked a little low, and it also always dropped about an inch when I put my popup on the hitch (thing weighs like 1200 lbs...). It would be pretty bouncy when towing the trailer and when i hit dips on the highway it would rub the tires.
still flexes:
Anyway, I was so pleased with the results that I recently installed a pair on my dakota to get about 1/2"-3/4" lift in the back as well when I cranked up the front torsion bars. Same results with the popup attached. Less settling.