Not that they need to be upgraded, but what options are available?

or if you go and get custom brackets made up you can probably go up to 300mm rears from teh B6S4... I think all are 22mm thick, the 300mm rotor might have a different offset tho. The 280's are actually from the front of a b6 not sold here... as indicated by the 8e0-615-301-B part number (301= front disc)

Stasis 298mm