They increased the race by 50 kilometers because Eddie and Bruton felt that the prices of the tickets were not worthy for the length of the race, which was 500 kilometers in 1 hour 37 minutes last year. So they changed it to 550 kilometers and it lasted about 2 hours or so. They will talk to the teams and see how the engines and drivers did, before approving the race be put to 600 kilometers for next year.
http://smg.photobucket.com/albums/v295/magnethead/2007_racing/IRL/
http://smg.photobucket.com/albums/v295/magnethead/2007_racing/IRL/