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 S4
Previously unavailable enthusiast driver aids are now optional, such as Audi's Sport Rear Differential, active steering and adaptive damping suspension (part of the Audi Drive Select Package). The front axle was moved by 6.1 inches to the front, which improved the weight distribution of the B8 Platform. Combined with the Sport Rear Differential Audi was able to greatly improve the weight balance and dynamics of the S4 over previous models.