Loeb raced sport prototypes in Le Mans. A (2007) F1 car is just a bit lighter, power fuller and heavier on the brakes than a sports car. It differences like a 2006 Group N to a 2007 WRCar. And it is special that a Citroen man drives a Renault car. Normally it is quite sensetive I believe, just as Japanese carnmakers don';t like to see their drivers in other Japanese cars.