72 Polara Leaf Springs

My leaf springs are sagging and twisted on my 72 Polara. I think someone removed a couple of the leaves. When I have a passenger or a full tank of gas the body rubs against the right rear tire.

I found two places that sell them. General Spring ($300/pair) and Firm Feel ($950/pair!!).

Any advice? What else should I be replacing while I'm down there? Should I bother with new mounting hardware? Are there rubber bushings or anything like that? What wears out?

Also, what shocks work well for this car? Thanks.
Author: Lord Alvin