actually, what I have in the rear are air bags inside the coils. I can raise the rear by adding more air, but once I got the headlights adjusted, I leave it alone - the bags inside the coils have no where to expand to, so they keep whatever height they are set on.

I have a real smooth ride, no matter whats in the trunk.
very simple install, I think $$99 set (two).

just google "air bags"
(I think that's how I found them)