Started in karting in 1980, graduating to the VW Polo Cup in 1983. He took a win at the Nürburgring Nordschleife, however his touring car career was over as soon as it began. As Kaufmann put it “Deliberately hitting other people’s cars is not my thing!”
He sat out 1984 and '85 due to lack of budget but returned in 1986 in the German F3 Championship with his own privately funded team. His efforts attracted the attention of Opel and he was offered a works drive at the end of the 1989 season.
In 1990 now with proper funding he started the season with two victories and a good lead in the championship. However it was not meant to be as technical problems with the new Opel engine put an end to further success that year.
In 1991 he was engaged in a duel with Tom Krisensen for the title but a crash resulting in a multiple fracture of his heel ended his season and his single seater career.
During his three years with Opel, the team worked with three different engine-tuning companies, which did no good to the development programme. Despite this, Kaufmann only just missed the championship twice.
Kaufmann did however managed to build up a good reputation as a development driver and remains grateful to Karl Maurer of Opel and Horst Schübel, the team owner, for giving him the opportunity to drive in Formula 3.
Kaufmann was back behind the wheel in 1993 with Freisinger-Porsche, where he was to stay until 2001. He appeared on the podium numerous times, helping Freisinger-Motorsport establish themselves on the international endurance-racing scene. They won the FIA-GT race at the Lausitzring in 2000, finished third overall in the 1999 season and finally won the Porsche World Cup in 2001. However, after Manfred Freisinger dropped Kaufmann in favour of Porsche works drivers, they did not part on the best of terms.
From 2003 to 2005 Kaufmann joined Wieth Racing to do development work on their Ferrari 550 Maranello and the Saleen S7R of Franz Konrad and Graham Nash.
He continues to race and does development work in Sports and GT cars.