How much big of a spacer will I need to clear the inside framerail/control arm/coilover with 275/35/15 A6 on a 15x9?

Car specs

2000 NB
Xida clubsports
-2.8 front -2.5 rear with ISC offset bushing front

I am currently getting minor rubbing at full lock with 225 rs3's. I am going to buy spacers to stop the rubbing but figured I would buy a spacer that will clear a A6 setup as that is probably what will be on the rim next year.

 

I ran 7mm with them at -3.2degrees in the front and -3.0 degrees in the rear but that was on a NA that is cut and flared.