Andy, no need to apologize to me. I am just frustrated with Ground Control. I like the Ground Control plates, I really do. What I don't like is that Ground Control was dishonest and continues to be. On the phone, the GC rep told me that the slots were only to make it easier to install and did not provide caster adjustment. I said "why are you advertising them as caster plates then?" and he said "I couldn't say." Since then, the advertisement has not been altered.
From what you are saying, I am guessing you might be able to move the plates a couple fractions of an inch farther towards the outside to gain some clearance. When I last looked under my strut tower, I did not get the impression that it would really help, but I will take your word for it. However, if you follow their instructions for drilling the mounting holes, (which I did, although I found them very poor) I do not think you will have any room in the tower to move your plates back enough to make any real difference.
My goal for the front suspension was adjustable camber and enough caster adjustment to get both sides even, that's all. I am not going to chop out my front fenders and this is not a race car, so I didn't need 14 degrees of caster or anything like that. But my options appeared to be:
AZ-Z adjustable front control arms for 600$ a pair, which includes adjustable tension compression rods, and would have given me a large range of camber and caster adjustment, and a very easy installation. Downside for a street car - no bushings.
GC camber/caster plates - 300$ a pair. Downside for a street car - no strut isolator. Installation was a nerve-wracking PITA.
What I ended up doing was having to buy these for another 200$:
For less than 100$ more than what I paid I could have gotten a larger adjustment range without hacking up my strut towers and making it necessary to weld on my strut cage mounts to the tower (can't bolt them up any more.) I think I probably would go with Dave's arms if I could do it all over again.
I like GC's products - I am running their coilovers too, and I like the way their bottom spring perch is tightened down with a screw that shortens their diameter instead of a set screw that goes into the threads. I just think their support is garbage and their advertising is misleading. Their instructions for the coilovers would have given me very little range in the rear if I had not gone to the trouble to mount the suspension with them tacked on to double check (and take it back off again.)