However, I just looked at the FIA GT standings and the Le Mans qualifying results, and it looks like there is a new sherriff in town.  The Prodrive Ferrari 550 appears to be the car to beat this year.
Looks like there are plenty of American cars in the field though.  Riley & Scott, Viper, Corvette, Saleen, and Panoz.  Too bad Mosler doesn't go to Le Mans.