Originally Posted by robert @ eas
The typical spacer sizing for ZCP with the 275 rear tire would be a 12mm spacer. I would say the 10mm spacer might be one that you should not have any issues with rubbing. As for the front, it would be typically a 15mm spacer, and you should be able to use a 12mm.
I use the 10mm spacer with a 10" ZCP GTS BMW rim and 275's. The car is lowered on B&G springs and I only rub when the car has additional passengers.