The Audi e-tron Spyder is being dubbed as a diesel-electric roadster, a pairing of active descriptors that further prove the advancement in automotive ingenuity. At first glance this may appear like merely a roofless, R8-based all-electric e-tron that was unveiled in Frankfurt in 2009. Rather, this is a longer and wider inclination that still features the plug-in diesel-electric powertrain. The 69-cell lithium-ion battery pack is good for 9.1-kilowatt hours, weighs around 220 pounds and is situated up front together with the electric motors. Though the diesel fuel tank carries just 13.2 gallons, the e-tron Spyder has an on-paper range of over 600 miles per fill-up thanks to its lithium-ion-fueled parallel help. While still just a prototype, the price has been valued at $2.7 million USD.