i have a ground control setup with koni adjustables in my '88///M5 and love it.i am running 18" wheels and the ride is better than the previous eibach lowering springs.the ground control setup is much better over bumps,the suspension doesnt seem to bottom out as much.i am using factory strut mounts.i am about to put ground control in my my wifes '91 ///M5.hope this helps. martin