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
In Europe, the 90 designation for five-cylinder models was dropped for this generation, and all saloons were badged as 80, regardless of which engine they had. Audi of America went the opposite direction, and began selling the saloon as the 90. B4s for the American market typically offered more luxury and style even in the standard version, such as automatic transmission, cruise control, air conditioning and leather seats, all of which were usually optional at additional cost (or standard) on European models.