As brutal a machine as Audi's R8 may be, there's an even more potent form made explicitly for the track.  Courtesy of Audi Sport, there's this: the Audi R8 GT3.

Known within Audi Sport as the R16 (it already built an R8 eight years ago), the new car is built to GT3 class rules.  As a result, don't look for Quattro - as GT3 prohibits all-wheel-drive, the R8 GT3 sends its power (reportedly over 500 hp) straight to the rear axle.

Although much of the car is virtually carryover from the production R8, the GT3 car adds things like a giant rear wing, full roll cage, heat extractors over the engine bay, new side skirts and a longer chin spoiler.

Production and delivery of customer cars is expected to begin in the fall of 2009.