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 A5
Available in coupé body, the RS5 features a 4.2 FSI engine rated @8250rpm and @4000-6000rpm, coupled with a seven-speed S tronic transmission and quattro permanent all-wheel drive with crown-gear centre differential and electronic torque vectoring. It has 19 inch alloy wheels in an exclusive five arm structure design with 275/35 tires (optional 19 inch winter wheels), diameter ventilated aluminum front brake discs (optional diameter carbon ceramic front brake discs), aluminum 8 piston brake calipers with RS logos in high-gloss black, electronic stabilization program with integrated sport mode, speed dependent servotronic steering, Audi drive select with three (4 with MMI navigation system) modes of operation (comfort, auto, and dynamic, optional custom), and optional dynamic steering.