In June of 2005, GM decided to start competing in the Grand-Am GT category with the GTO.R with Katech engines campaigned by TRG in Pratt & Miller prepared cars. Despite the late start the program was able to make an impressive list of achievements. The GTO.R brought home four victories in eight events, setting the stage for a complete season run at the championship in 2006.
- 8 first place finishes
- 6 second place finishes
- 6 third place finished
- 19 consecutive podium finishes overall
- Grand-Am GT Manufacturer’s Championship
- Grand-Am GT Driver’s Championship
- Grand-Am GT Team Championship