First, check to see if you have a broke leaf spring by looking at them from under the truck. If they are broke you will be able to tell. If all is well, go ahead and level the truck with the torsion bars. After you tighten them take a quick drive and check them for level and adjust acordingly.
Just enough to level the driver side to the passenger side. I have the D sitting level front to back at stock hight. the only thing I want to do to suspension is put a set of Bilstien shocks on, hopfully it will stop the hop in the rear of the D when I hit bumps in road.
Bilstiens are great. I have used them on all my trucks in the past. On my Dakota, I put on some Rancho RSX's and I cant tell a difference over the Bilsteins. You cant go wrong either way. It will make the ride MUCH better.