How is it eating the tyre? Just over cambered?
I struggled for alignment with mine for a while, TWT and such cant align for shit, eventually took it to the dealer and they got it spot on. Also remember with stock sports setting is pretty aggressive, so you will chow your inners quickly, some guys prefer to have that dialed out to prolong the life of the tires, but no real point in having an M3 if you doing that.