So I got my new Ground Control rear top mounts in the mail yesterday. Get this, they're listed as camber/caster adjustable!
The tops are slotted, which might just be for fitment purposes, but I'll certainly be able to finagle some fore/aft adjustment out of them if I so desire.
What I can't figure out is how changing the caster in the rear does anything... since you don't steer with those wheels, positive caster isn't going to add (well, subtract) dynamic camber. Does rear caster have some sort of effect on the camber of the tire as the strut compresses?
Now I'm guessing that the invoice is just a generic printing, and the slots are actually just to handle tollerance issues in the car. But as a thought exercise, what would rear caster adjustment gain you?