why do all the aftermarket coil over kits have the coil over mounted to the lower control arm? I don't see why it couldn't be mounted to the upper control arm, with the other end attached to a reinforced/heavy duty stock style upper shock mount.
when mounted to the lower control arm you can move the attachment point out close to the end of the arm for better response, thus allowing you to use a softer spring rate with the same overall performance.