Found this Offset Calculator whilst I was looking for wheels. Easy to use and pretty helpful i reckon:
Wheel Offset Calculator
Need pinstriping? : www.crazypainter.com
A4.. 1.8T.. Remapped .. Saloon.. Atlas Grey.. Votex Kit..
Yeh it is good, Simon beat you to it by a year though posting it in the FAQ section!
2003 A4 Avant 2.5TDi quattro NOW BREAKING ADVERT Free (broken) wiper linkage LINK