I don't think I can get any thinner than 3mm... (the sketchy part would be if I removed them all together, and cut my springs). I love the way your wheels fit in your arches... I'm only running 15"s... your's are 17" and look sweet. I was kinda looking for a quick fix, instead of buying lower springs, and bigger rims. Something like deeper spring cups would tie me over until 17's become affordable to me... on the other hand, if I'm changing the cups, I might as well just change the springs, right?
Do you have any clearance issues with your rims? Think you could tak a few pics of your wheel gaps for me, Graham?