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.
Audi A8
Audi introduced the S8 4.2 quattro into the European market in 1996. The S8 followed the naming convention of other high-performance Audi "S" models such as the Audi A6-derived S6 and was similar in vein of Mercedes-Benz AMG models. In markets such as the UK, the S8 was only available with the automatic transmission. Cosmetically, Audi differentiated the S8 from the A8 with solid aluminium alloy door mirror housings, chrome-effect beltline and lower front grille trim, and polished twin exhaust pipes, along with subtle "S8" badging. 14-way power adjustable and heated sports front seats with memory function were fitted as were heated rear seats. Standard alloy wheels were 18-inch cast aluminium alloy "Avus" six-spoke style. After the 1999 facelift, 20-inch polished nine-spoke RS wheels became an option. In 2002, 18-inch nine-spoke RS wheels became a no-cost option.