It was a series for Le Mans Prototypes (LMP) and Grand Touring (GT) race cars divided into 4 classes: LMP900, LMP675, GTS, and GT.
Little was changed between the 2002 and 2003 schedules; the Grand Prix of Washington, D.C., and Mid-Ohio Sports Car Course did not return, but both were instead replaced by the return of the Grand Prix of Atlanta at Road Atlanta.
The Grand Prix of Mexico was originally scheduled for April 6 at the Autodromo Hermanos Rodriguez but was canceled due to financial issues.
Points are awarded to the top 10 finishers in the following order:[5] Exceptions being for the 12 Hours of Sebring and Petit Le Mans which award the top 10 finishers in the following order:[5] Cars failing to complete 70% of the winner's distance are not awarded points.
Teams only score the points of their highest finishing entry in each race.