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 80
Audi developed a sports version of the Coupé in 1990, called the Audi S2. This replaced the famous Audi Quattro (launched in 1980) and featured the well-proven 2.2-litre in-line five-cylinder 20-valve turbo petrol engine from the Audi 200 20V, which was derived from the engine used in the Audi Quattro. A similar version of the engine was used in the Audi 100 based S4 (the 'Ur-S4'). The S2 came as standard with quattro permanent four-wheel drive, and featured a heavy-duty 5-speed manual transmission, and was capable of 150 mph.