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 80
Most petrol versions could be ordered with quattro permanent four-wheel-drive; at the time, however, it could only be combined with a five-speed manual transmission. Additionally, Audi built about 2500 units of the "Quattro Competition" for the German and European market. It was a street homologation of the B4-based Super Tourenwagen Cup (STW) race car saloon with four-wheel drive and a modified , 16-valve, two-litre petrol engine. The powertrain had its roots in the two-litre, four-cylinder inline engines that most European Audi 80s were equipped with at the time. On the outside, the "Quattro Competition" featured the same bumpers as the S2, V6 headlights, and a rear wing mounted on the bootlid. Together with the S2 and the RS2 Avant, the "Quattro Competition" has become an increasingly rare and highly sought-after collector's item.