Well after a bit of research I can semi-safely say they'll fit. The most easily searchable car that runs 288mm discs (like those on the 1.9 TDi A3) is the Mk3 VR6 and they can run 15" wheels so you should be ok. You should double check the offset though, since there'll be very low clearance.
17" is the smallest that'll clear the S3/3.2V6 356mm brakes, maybe that's what you're thinking of Snipe.
Just as a 'get out of jail free', this is based entirely on internet research done at 2:30am and in no way should be held as gospel.