Ground controls aren't cheap quality by any means. Actually most e30's on coilovers are probably running the GC with Koni setup. It's cheaper because you have to actually modify the front factory strut tube to do it, and buy parts individually.
I was just on AMI's site and they don't sell coilovers, they just sell spring and strut combo's.
85 325 - Turbo M52B28.