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 V8
At the initial launch of the Audi V8, the only offering was the 3.6-litre powerplant, which displaced . This V8 engine was DIN-rated with a maximum motive power output of at 5,800 revolutions per minute (rpm), and generated a torque turning force of at 4,000 rpm. In August 1991, Audi introduced a 4.2-litre engine, displacing , to complement the choice of the existing 3.6-litre V8. This shared many components from the 3.6 V8, and the 4.2 unit was identical to the optional V8 used in the Audi S4 (aka "Ur-S4"), sharing the same rated outputs and ABH identification code. Like the 3.6 V8 model, the existing four-speed automatic gearbox remained available. However, a new six-speed manual gearbox replaced the five-speed manual. This powerplant is identified by chrome 'V8' badges on the front grille and at trunk lid, where in some cars also '4.2 quattro' badge is present.