18x8+48 with 215/45 have been reported to rub in rare circumstances
18x7.5+48 with 225/45 do rub in rare unusual circumstances - I have them.
Mine have rubbed once. You have less guard clearance with 18x8+45, so:
In unusual circumstance, 225/45 and 215/45 are certain to rub. 225/40 less so but still possible.
How often? Less than once in six months. I don't see it with mine in normal circumstances. But I know it can and will in the right circumstances.
guard rolling is a good idea because of this.