The images show what looks more or less like a normal R8, except that it has no tail pipes, the window for what would be the engine bay is opaque, and it wears an e-tron badge on its hood, as well as vinyl e-tron lettering on the sides and windshield. Minimal air inlets up front--presumably to reduce drag--are also visible, while a high-voltage sign on the driver's side rear quarter window cautions of the danger of electric shock. The license plate says "HOCHVOLT," German for "high-voltage."
This lack of secrecy in the nature of the car might seem somewhat counter-productive to actually operating in secret, but Audi doesn't appear to be concerned with flying under the spies' radar. In fact, the prototype spotted in testing here is dead ringer for the car shown in Audi's latest official video demonstrating the process of creating the sound for the R8 e-tron. Even with that official peek at the car, this is our first and best look at the near-production version of the car yet.
2013 Audi R8 e-tron test mule spy shots