This link is for an article on AudiWorld with the Audi AG (German) press release for model year '02 A6's. Cars are German spec, not U.S., but U.S. cars should be very similar. Likely differences on U.S. cars include body colored lower panels, not matte black, and slightly larger bumpers. The car looks very much like the '01 A6's. If you go and look at those, you'll be looking at something very similar. Revised stereo controls, a chrome ring around the instruments, and some new interior colors appear to be the only significant interior changes.
A recent conjecture by a knowledgeable poster AW suggests that the former sport suspension may now be the standard suspension. May include 3/4" lower ride height. I'd like that, if they retain the availability of the non-sport seats.