In stock form, the Audi R8 is a potent supercar packing a naturally aspirated 5.2-litre V10 making 611 bhp (456 kilowatts) and can reach 62 miles per hour (100 kilometres per hour) in 2.1 seconds for the new Green Hell edition. A stock example would never be able to keep up with Underground Racing's twin-turbo coupe, though. It recently set a record among R8s by being the first one to break the seven-second barrier in the quarter-mile.
Underground Racing's R8 sets the record in style. Off the line, the car lifts its front wheels into the air and rockets away. It manages to cover the quarter-mile in 7.695 seconds at 196.76 miles per hour (316.7 kilometres per hour).
To make the time even more impressive, this R8 retains a full interior, and Underground Racing doesn't strip off anything to reduce the weight so that the vehicle tips the scales at 1,730 kilograms (3,815 pounds) without a driver.
The car runs Underground Racing's X Version tune. The company claims that it makes 1,200 bhp (895 kilowatts) at the wheels when running on 93-octane fuel. On race fuel, the output is somewhere between 2,200 and 3,000 bhp (1,641 and 2,237 kW) at the wheels.
In addition to the twin-turbo setup, the car uses Underground Racing's upgraded DCT gearbox that features billet for the gears, input and output shafts, final-drive gear, and AWD shaft. There's also a standalone engine management system.
Underground Racing also uses this R8 for longer runs. The same car was previously able to hit 244 mph (393 kph) in the standing half-mile (804.7 metres).