Quattroholic has put up some fantastic scans from an Audi AG book about the 1991 Audi Avus Concept. Hard to believe this was 20 years ago. A lot of the design cues from this car directly influenced future products like the Bugatti Veyron, Audi TT, and Audi R8. The Avus was heavily influenced by the legendary Auto Union race cars of the 20s and 30s—and represented a turning point in modern Audi design.
check out the full scans at:
http://www.quattroholic.com/2011/04/hi-res-scans-of-original-1991-audi-avus.html