American Le Mans Series Classes of Competition

Premier high-tech Le Mans prototypes (LMP) feature exotic purpose-built race cars such as the Audi R10, Lola B06/10 and Zytek O4S. Minimum weight must be 925 kilograms (2,045 lbs.). These ultra-sophisticated racing cars are capable of reaching speeds in excess of 200 miles per hour and can achieve upwards of 600-700 horsepower.

Smaller and less powerful prototypes have a minimum weight of 775 kilograms (1,708 lbs.) and a top speed of 180-200 mph. These purpose-built race cars include the Acura ARX-01A, Lola B05/40 and Porsche RS Spyder. Engine horsepower capacity runs in the 500-550 range. The three Acura-powered cars will compete in the LMP2 class in 2007.

Highly modified, production-based, two-wheel-drive Grand Touring (GT) cars have horsepower capabilities of 600-650 and top speeds ranging from 180-195 mph. Almost as quick as prototypes, GT1 cars include the Aston Martin DBR9, Chevrolet Corvette, Ferrari 550, Maserati MC12 and Saleen S7R. A higher minimum weight of 1,125 kilograms (2,480 lbs.) reduces cornering and braking ability and limits overtaking of prototypes.

Moderately modified, production-based, two-wheel- drive cars that can reach speeds of up to 180 mph with horsepower capacities of 450-500 and minimum weights of 1,125 kilograms (2,480 lbs.). GT2 cars include the BMW M3, Ferrari 430, Panoz Esperante GTLM and Porsche 911 GT3 RSR. IMSA also provides for cars with as many as four seats to compete as a GT2 subgroup (GT2S). GT2S cars such as the BMW M3 and Lexus IS 350 are eligible for Series championship points and podium positions, but are not eligible to compete in the 24 Hours of Le Mans.