Audi A6
Audi made a high-performance, 4.2-litre V8 engine (parts code prefix: 077, identification code: AEC) with a Bosch KE-Motronic ECU available as an option in the original European S4s, and made the decision to continue to do so with the S6, making a version of the 4.2 available as an optional upgrade over the 2.2-litre inline five-cylinder turbo. Unlike the five-cylinder turbocharged version, the V8-powered S6 was supplied with a four-speed automatic transmission as standard, but kept the quattro four wheel drive. A six-speed manual gearbox was also available as an option.
Audi A4 DTM
Like all DTM racing cars, the A4 DTM resembles its A4 production equivalent only in cosmetic appearance. The A4 DTM is constructed with a carbon fiber reinforced plastic monocoque chassis and an integrated fuel tank. Powered by a Audi naturally-aspirated V8 engine, it has a power output of approximately and a maximum torque of more than . The rear-wheel drive A4 DTM also has a sequential 6-speed transmission, a 3-plate carbon fiber clutch supplied by Sandtler (2004-2010) and ZF (2011), and an adjustable multi-disc limited-slip differential.