Just like the VLN series with its 4-hour races, the 24h race is mainly aimed at amateurs, in order to fill a starting field of around 200 cars.
Due to various changes and versions of the Grand Prix Strecke, the overall length of the track varied from the original to nearly of the maximum length configuration which was in use in 2002 and 2003, after the GP track had been extended by the Mercedes Arena.