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 1993, the S2 received some cosmetic updates, including new AVUS style alloy wheels, ellipsoid beam (projector) headlamps and clear front indicator lenses. This coincided with the introduction of the five-door S2 Avant, along with a limited run of four-door S2 sedan models, of which 306 were produced. The S2 saloon and Avant are actually based on the next generation B4 platform, and feature a lot of similarities in the rear axle support system to the later B5 A4 quattro. The B4 platform S2 Avant was also used between 1993 and 1995 as the basis for Audi's RS2 Avant super-sports estate, which was modified for Audi with assistance from Porsche.