spring stabilizers...

has anyone had any experience with them?
Ring Type Coilspring Stabilizer (http://jcwhitney.com/productnoitem.jhtml?CATID=14833&BQ=jcw2)
i wanted to lift the back about 1/2-1". the product says up to 2", but i dont see how a solid piece can be adjustable. any help would be appreciated.
thanx.

Its not solid it is teflon rubber, which may breakdown over time or compress like any bushing. But that would be the best way to raise your rear. Comptech uses teflon sleeves in between their coilovers perch and spring to reduce friction. The teflon is up to the job the rubber will just dampen or limit the spring from moving on the perch.

I would however get demensions on the rubber to make sure it will seat on your perch properly.