I've got the same issue on the SDL. I have not replaced the springs yet, but am planning to do so.

Some questions:

Have you measured the height of the fenderwell above the ground, before and after the spring install? Mine is currently at 24.75 inches prior to the spring install. This is about 2.25 inches less than the front.

Did you change the rubber bushing that sits above the spring?

What is the condition of the subframe mounts? These can give up .75 inches if they are mashed flat.

I sure would like to avoid wasting my time with springs if there are other, more important variables.