For front, rule of thumb is to avoid 10mm spacers since hub lips vary. If it were me, I'd go 5 or smaller, or 12 or bigger on the fronts to avoid any issues. For the rears, any size works
15's would be flush to slight poke. 12's on all 4 corners should be flush without too much risk of curbing. Either way, make sure to get longer bolts.
Recaro | AST | Vorshlag | Quaife | Stoptech | Volks | Autosolutions | BMW Performance
Click here for my track videos