How do you adjust the camber on the FKs.
On the Ledas the top bolt, on the picture in your post, when turned pushes the hub in and out which sets the angle of the wheel.
I imagine if you are re-drilling the holes you need to be really careful not to effect camber settings.
I think I would give the GAZ a miss. Although I have not tried them I did have some on order through KTEC and specced some different spring rates to standard. I was waiting for them for about 7 weeks before I cancelled them, KTEC blamed GAZ for not delivering. Poor customer service. Although saying that what about these.
http://www.k-tecracing.com/show_product.asp?id=1776.
You could also look at the leda/muki suspension, and get a set developed for a cupped 182.
I personally would not drill the coilovers out as a failure would be nasty. Its one of those things you would probably get away with it but is it worth the slight risk.