Audi S6
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.
Quattro (four-wheel-drive system)
Starting from 1988 on older generation Audi 100 C3 platform and Audi Quattro until the end of their production, and on new generation B3 platform (1989–1992) Audi 80/90 quattro, B4 platform (1992–1995) Audi 80, Audi S2, Audi RS2 Avant, C4 platform (1991–1994) Audi 100 quattro, Audi S4, later C4 platform (1994-1997) Audi A6/S6.