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 100
Audi released the C4 "(a heavily revised C3)" in late 1990 in Continental Europe and 1991 in other markets, including the right-hand drive British market. The C3-platform Audi V8 continued to be sold as a separate line. The major change for the C4 was the introduction of a 2.8 L, 90-degree, SOHC 12v, V6 engine. It was later joined by a 2.6 L variant, of the same configuration as the 2.8 L unit. They are essentially the same engines offered in the 1992, B4 Audi 80. The option of quattro permanent four-wheel drive was an option across the range, and the Audi 100 quattro was available with a ZF four-speed automatic gearbox.