And it's all due to what Audi suggests are unspecified advances in battery technology.
It's part of the latest changes to Audi's future product portfolio since Ulrich Hackenberg arrived in July to run the research and engineering group at Audi, which is part of the global Volkswagen Group.
New battery technology means the R8 e-tron's range has "grown significantly," an anonymous Audi insider told Drive, to almost 250 miles (400 km) from the previous 135 miles (215 km).
The advances are due to an unspecified "alternative chemical process" (presumably a more advanced electrode chemistry) that significantly boost energy density of the electric R8's battery pack, which in earlier prototypes contained 48.6 kilowatt-hours of energy.
The latest development prototypes of the R8 e-tron use a pair of 140-kilowatt (188-horsepower) electric motors powering the rear wheels, which are controlled using Audi's torque-vectoring control software to ensure maximum traction and power delivery between the two wheels.
Total torque provided to the rear wheels is 605 lb-ft (820 Nm), giving 0-to-62mph acceleration of just 4.2 seconds--slightly slower than the (lighter) 2009 Tesla Roadster, at 3.7 or 3.9 seconds.
The weight of the R8 e-tron, in fact, likely reflects its genesis as a gasoline-powered vehicle. The electric R8 weighs in at more than 3,900 pounds (1780 kg), or 460 pounds heavier than even the most powerful V-10 version of the existing Audi R8.
Audi R8 e-tron track drive, Berlin Tempelhof AirportEnlarge Photo
The many twists and turns of the R8 e-tron's tortured survival started way back in 2009, when it was revealed at that year's Detroit Auto Show.
As late as July 2012, Audi was touting the new electric-car lap record it had achieved at the famed Nürburgring racetrack.
Then the project was seemingly canceled, for reasons ranging from worries about its limited range to concerns that it would not be profitable.
That appears to have changed with the July arrival of Hackenberg, who was responsible for VW Group's first production plug-in cars, the Volkswagen e-Up and e-Golf that entered production this year.
He also oversaw the limited-production Volkswagen XL1 diesel plug-in hybrid and the upcoming 2015 Audi A3 e-tron plug-in hybrid.
Audi has ambitious plans to expand its lineup to 60 models by the end of the decade, so it may see the all-electric R8 supercar as a necessary component of those plans.
Will we see R8 e-tron supercars in Audi showrooms next year?
If history is our guide, there may yet be more twists and turns in the car's story before then.