When getting replacement parts, it is always good to have parts numbers in hand to help the parts counter staff. For example, many parts staff have never heard of an UrS4 or UrS6 and will try to tell you that you are mistaken and tell you that you mean a B5 S4 or a C5 S6. Same with S2 (don't you mean A2 sir?)/ If you can give them the part number, they will find the proper listing much faster and more accurately. On this basis, these websites will help you to preserve a very well designed and constructed sports sedans, coupes, and avants, still representing the Audi brand well, even as they push to and past the 20 year milestone.
The general Audi Parts info link:
http://audi.7zap.com/en/rdw/
Example UrS links
UrS4 (remember our engine is the AAN):
Audi 100 quattro (A10Q) 1993 year Group Parts Audi USA
UrS6 (ditto, AAN):
1995: Audi A6/S6 quattro (A6Q) 1995 year Group Parts Audi USA
1996 (95.5 for the Americans):
Audi A6/S6 quattro (A6Q) 1996 year Group Parts Audi USA
1997 :
Audi A6/S6 quattro (A6Q) 1997 year Group Parts Audi USA
The general Audi Parts info link:
http://audi.7zap.com/en/rdw/
Example UrS links
UrS4 (remember our engine is the AAN):
Audi 100 quattro (A10Q) 1993 year Group Parts Audi USA
UrS6 (ditto, AAN):
1995: Audi A6/S6 quattro (A6Q) 1995 year Group Parts Audi USA
1996 (95.5 for the Americans):
Audi A6/S6 quattro (A6Q) 1996 year Group Parts Audi USA
1997 :
Audi A6/S6 quattro (A6Q) 1997 year Group Parts Audi USA