Check my avatar, 312's going under RS4s very soon. They do fit under 16s I believe (diameter is ok, just depends on the wheel spoke depth. Audis all have wheel with no real dish, if at all, so your range of options should be fine). You need 5x100 pcd, so a set from a TT or S3 Audi will be fine. Recent a4/s4 series are not right at 5x112. Binliner was selling a set of tt competitions, and another member just replaced his. They look awesome. I'd have them if I wasnt on the other side of the planet.