So I've been thinking about getting spacers for the e36 as the wheels (especially fronts) look lost, but not sure what size to go for. Is there a way to work out if it's 10mm - 12mm -15mm and so on or just take a chance and hope there's no rubbing issues etc.

I presume rubbing the arch with suspension movement and rubbing the arch liner whilst turning are common things but what's a safe size to avoid this? Would also consider spacers on the rear too, but again, how to know what size to go for?

Any advice?