Four new A4 DTM cars, entered by Audi Sport Team Abt Sportsline and driven by defending champion Mattias Ekström, and Tom Kristensen, Allan McNish and Martin Tomczyk, lined up on the DTM grid in 2005. Audi Sport Team Joest looked after the four year-old cars for Christian Abt, Rinaldo Capello, Pierre Kaffer and Frank Stippler.
Audi Sport Team Abt Sportsline started the 2005 DTM season with a completely new car thanks to a change of production model. The new A4 DTM, labelled internally with the project number R12, easily recognisable at first glance by the new singleframe radiator grille started from pole position on its debut and won three races against the toughest competition. Last year's champion Mattias Ekström and Tom Kristensen finished the exciting season in second and third position.
Christian Abt, in the Audi Sport Team Joest Audi A4 DTM, was the best placed driver of a year old car.