Audi Ur-S4 / Ur-S6
The Ur-S4 was produced from 1991 to 1994, while the Ur-S6 was produced from 1995 to 1997. They both featured a 2.2 litre, 5-cylinder engine with turbocharging and an intercooler, with of torque. In Europe, V8-powered versions of both S4 and S6 were available. The S4 version sported a engine (the same "ABH" engine as in Audi V8), the S6 had an upgraded engine "AEC" with . American versions featured a 5-speed manual transmission and in Europe a 6-speed, as well as a 4-speed automatic transmission could be substituted.
Quattro (four-wheel-drive system)
Starting from 1988 on older generation Audi 100 C3 platform and Audi Quattro until the end of their production, and on new generation B3 platform (1989–1992) Audi 80/90 quattro, B4 platform (1992–1995) Audi 80, Audi S2, Audi RS2 Avant, C4 platform (1991–1994) Audi 100 quattro, Audi S4, later C4 platform (1994-1997) Audi A6/S6.