I was watching the St Pete ALMS race on Speed yesterday. Why does ALMS have the GT1 class if there is only one team competing? Similarly P1 only has one car capable of winning. The racing action in P2 (Acura vs Porsche) and GT2 (Ferrari vs Porsche) is really compelling. I guess the P1 Audi does add excitement by occasionally running into the cars that are really racing.

 

Because they're mimicking the full Le Mans rules. Corvette and Audi like to run in ALMS even though their 24 Heurs du Mans competitors don't.