It featured a series of races for GT1 Grand Touring and GT2 Series Grand Touring cars, the former more powerful and highly developed and the latter remaining closer to the production models on which they were based.
[1] Additionally cars from National Championships (Group 2) and from Single-make Cups (Group 3) were permitted to participate in championship races but could not score points towards the various awards.
[1] The championship season began on 10 April 2005 and ended on 25 November 2005 after 11 races.
Points were awarded at each round to the top eight finishers in both the GT1 & GT2 classes on a 10 8 6 5 4 3 2 1 basis except for the Spa 24 Hour event were “double points” were awarded in three parts as follows:[2] The GT1 Championship for Drivers was awarded to Gabriele Gardel of Switzerland, who drove a Ferrari 550-GTS Maranello for the Larbre Competition team.
The GT2 Cup for Drivers was awarded jointly to German drivers Mike Rockenfeller and Marc Lieb who shared a Porsche 996 GT3 RSR entered by GruppeM Racing.