Brian:

I saw the note in your gallery.

For a sagging rear end I presume you are aware of AirLift helper airbags, I used them on my old pickup truck when I went to Alaska, I was about one ton overweight. Firestone also has a airbag helper product too.

Because I have a van, I'll probably go with the Talon replacement (leaf spring delete) air suspension system.

Hellwig also offers an air assist suspension product.

Kelderman offers a leaf spring delete air suspension system too, but their method doesn't appear to adapt well with my van.

Of note though is that Helderman has a front coil spring delete air suspension system too (versus the coil spring air assist bag that goes inside the coil), but be careful with the front air systems as proper pressure (height) is critical else your steering geometry degrades.