siliconed my mates g60 arches on with large rivets on the bottom. used an angle grinder to get rid of any fouling on the arch + on the arches themselves. I'd be wary about using spacers unless you get proper ones likethe eibach ones with the corect bolts, otherwise can be very dangerous, i know, my wheel came off on a b road, bloody nightmare it turned out to be.
mates car has been dropped 60mm on koni coilovers.