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 RS 4
The B8 RS4 is using the Volkswagen MLB platform. It is also only available with the dual clutch S-tronic gearbox configuration, allowing the car to accelerate from in 4.7 seconds. Compared to the related B8 S4, the RS4 features larger bumper air dams and features a double exhaust tailpipes compared to the S4's double twin (quadruple) exhaust tailpipes.