2001-2005 Audi R8

Images copyright Patrick Michl and Michael J. Fuller
Text copyright Michael J. Fuller

The leading edge shape of the rear fender is more rounded and pronounced inboard.  Looking at the relationship of the turbo scoop and  the leading fender edge, the turbo scoop has moved rearward compared to '00 (below).
2000 Audi R8 turbo scoop.
The rear body work center section is narrower compared to the 2000 R8's, with it coming almost to a point at the trailing edge of the car.  The entire engine covered has been lowered noted by the clearance bulges for suspension.
Post race (Mosport) flow-vis. shots of the rear of the R8.  Note the air bunching up on the in-board side of the rear fender as it approaches the rear spolier (not shown). 

ęCopyright 2001, Michael J. Fuller