• Daytona Prototype (DP): This class was introduced to replace the two existing Sports Racing Prototype groups. To control costs, the cars used a tube frame chassis rather than the expensive composites used to construct most prototype race cars. Also, expenses were contained by limiting modifications and implementing rules that would be in place for five years. Approved to produce the first generation of Daytona Prototypes - for a cost of approximately $400,000 were: Riley Technologies, Doran Designs, Crawford Race Cars, Fabcar Engineering, Chase Competition Engineering, Picchio and Multimatic. Costs were also controlled by restricting the engines to production based motors supplied by Pontiac, Lexus, BMW, Porsche, Ford and Infiniti. Engine displacement was used to determine the weight of a car and whether a five or six-speed transmission could be utilized.
• Sportsracing Prototype II (SRP II): These are purpose built open cockpit race cars from manufacturers such as Lola, Kudzu, Pilbeam and Piccio. The engines used in SRP II cannot be turbocharged and are limited to a displacement of three-litres. The maximum weight for cars in the class it 1,750-pounds.
• Grand Touring Super (GTS): In 2003, the class was expanded to include cars that formally competed in American GT. As a result, there were two sets of rules to accommodate Unibody and Tube-Frame vehicles. Overall the production based Unibody cars were lighter than their Tube-Frame counterparts. Normally aspirated and turbocharged engines were permitted for the Unibody vehicles were as the Tubeframe cars were limited to an iron or aluminum V8 engine with a maximum displacement of 375-cu.in..
• Grand Touring (GT): This category is for production based vehicles such as the BMW M3, Chevrolet Corvette, Ferrari 360GT and Porsche GT3RS. Turbocharging is not allowed and maximum engine displacement is 6.0-liters.

As in the past, the season opened in February with the Rolex 24 at Daytona International Speedway and ended at the same track in November. In between these two weekends, there were events at Homestead-Miami, Phoenix International Raceway, Barber Motorsports Park, California Speedway, Watkins Glen, Mid-Ohio Sports Car Course, Mont-Tremblant and Virginia International Raceway. There was a total of twelve events with the series competing at Watkins Glen twice and Daytona three times.

Le Circuit Mont-Tremblant was race ten of the twelve rounds contested during the 2003 Grand-Am championship. Mont-Tremblant is a track with a rich history – in addition to featuring the F5000, Can Am and Trans Am series it also hosted the Canadian Grand Prix in 1968 and 1970.

This event would be six hours in length around the 15-turn 2.65-mile road course. The car count was lighter than usual as many competitors did not want to make an effort to cross an international border. There was a total of twenty-four starters. However, the grid included nine Grand Am Cup entries to bolster the car count.