The Audi RS6 featured a twin-turbocharged version of the corporate 4.2 Litre V8 engine, which had originally been developed for the 1994 A8. With the aid of the turbochargers, output rose to 444 hp (331 kW) and 415 ft·lbf (560 Nm) of torque. The combination of the V-8 and the turbochargers helped give the RS6 an exceptionally wide power band, with peak torque available from 1950 to 5600 RPMs.
The RS6 was available only with Audi’s Quattro All-Wheel Drive system and a 5-speed "Tiptronic" transmission, the same unit that was being used in the W12 powered A8, chosen because none of Audi’s manual transmissions could cope with the RS6’s high torque output. The RS6 also served as the debut model for Audi’s Dynamic Ride Control (DRC) system. The system is mainly mechanical, and uses a pump to keep pressure in the shock abosorbers during cornering to counteract rolling and pitching. The system is "intelligent", it is able to adjust the stiffness at each shock absorber constantly to maintain both a comfortable ride and high grip. However, DRC’s main advantage is that it operates without the need for most of the complicated electronics required in similar systems from Mercedes Benz and other competitors.
According to testing by Car and Driver magazine, the RS6 can accelerate from 0 - 60 mph (0 - 96.6 km/h) in just 4.4 seconds, 0 - 100 in 10.7 seconds and has an electronically limited top speed of 155 mph (250 km/h), however the vehicle can reportedly hit 170 miles per hour or more in unlimited form. It can stop from 60 mph (96.6 to 0 km/h) in 118 feet (35.97m), thanks to its large 365/335 mm (14.4/13.2 in) front/rear brakes, and an uncommon eight-piston design in the front.
There was also an RS6 Plus version of the car producing over 480 bhp and topping 180 mph. The car came only as an avant and was sold only in European markets. It lasted for just one model year but quickly sold out once it was released.
New versions of the S6 and RS6 will soon be in development, based on the new A6 platform introduced in 2005 (for the 2006 model year).