Originally Posted by kaiv
That doesn't say much in regards to OP's question. A 10.5" ET25 will be 11mm closer to the strut compared to your 10" ET20.
Well then that definitively says that you can't run 18x10.5 on a KW CS setup (without removing helpers to raise spring perch). Mine rubs with no spacer and does not rub (by just a couple mm) with a 5mm. There isn't enough room in the fender to run a 15mm spacer or I'll hit the other side. I don't know how TCK's spring perch compares to mine, but I would be shocked if someone is running 18x10.5 et20 with KW CS and isn't rubbing.