Ahhhh okok I see thank you! probably not gonna do it now until I get wider wheels. Thank you!If you're after RS4s, there's only two sizes they make (P275/35R19 & P305/30R19) that would "fit" the OE wheels, and I wouldn't recommend those sizes, especially the rear option at a P305/30R19. I had RT660s in that size temporarily mounted on the OE rears, and they were quite balloon-like, and very squirmy on highway pulls and in bumpy corners.
If you're set on those tires at those sizes, it's time to get wider wheels.