Audi S4
Audi's quattro four-wheel-drive system was standard on the C4 S4/S6; a first-generation Torsen-based system which used the "T-1" automatically biasing centre differential (ATB) was used on vehicles equipped with manual transmissions, while a transfer box based system was used on vehicles equipped with an automatic transmission.
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.