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 A4
The first generation Audi A4 (known internally as the "Typ" 8D) debuted in October 1994, with production starting November 1994 and European sales commencing in January 1995 for the 1995 model year. North American sales later began in September 1995 for the 1996 model year. It was built on the Volkswagen Group B5 (PL45) platform, which it shared with the fourth generation Volkswagen Passat (B5, "Typ" 3B). It had a front-mounted longitudinal engine and front-wheel drive. Many variations of the A4 were also available with Audi's quattro four-wheel drive system. The A4 was initially introduced as a four-door saloon/sedan; the Avant (estate/wagon) was introduced in November 1995 and went on sale in February 1996.