In 1997 the scene changed strikingly for the A6. With the introduction of an ambitious new design (C5) and a new pack of engines the A6 moved up a notch and was positioned alongside the hegemonious 5-series and the solid E-class. The new A6 presented itself with a wide range of engines and configurations. The crisp 2,4 and 2,8 V6 engines presented the bulk of the A6 programme but the resilient 2,5 V6 TDI and the powerful Audi S6 also deserves mention. As an alternative to the manual transmission a 5 speed Tiptronic automatic transmission was also available.
In 2000 the A6 received a facelift which saw little change in the design of the car but presented a few notable changes in terms of engines. The 1,8 litre engine was removed and replaced by a 2,0 4 cylindre with 130 bhp. The 1,9 litre tdi was tweaked into producing 130bhp and 310 nm. The 2,4 engine now packed 170 bhp and the 2,8 litre V6 was replaced by a 3,0 litre V6 boosting 220 bhp. The turbocharged 2,7 litre got a tweak on the turbo resulting in 250 bhp and 330 nm. The diesel V6 got a mild tweek as well resulting in 155 bhp (later 163) and 310 nm (later 350nm). A new more powerful V6 diesel was also introduced presenting 180 bhp and 370 nm. Also new was the revolutionary Multitronic drive by wire automatic transmission avaliable in the 2,0 - 2,4 - 3,0 and 2,5 tdi(155).
All models, except the 2,0 petrol and 1,9 tdi, were avaliable with Audi's four wheel drive system - Quattro.
In the late years of the A6 C5 design, a monstrous Audi RS6 model was presented. Producing a staggering 450 bhp and 560 Nm it propels the A6 from 0-100 km/h in 4,7 sec and on to 200 km/h in under 18 seconds. This model saw the end of the C5 design which was replaced in 2004 by a new model.