Uhhh... I'm sorry for being extremely rude, but it's very evident that you don't know anything about racing, or F1 cars.goukipauHmm, maybe you do not know this, but the nurburgring is a very high speed track. The F1 car cannot compete agains the group C cars there I think!
The F1 car cannot go above 350 kmh, or the wings must be extremely flat, so less to 0 downforce is created. Then the group C cars are faster on the straight...
Just as Le Mans, F1 cars don't have a chance there either.
Gouki
Top speed certainly isn't the most important thing in racing (unless it's an oval). Despite the Nurburgring being very high speed, and F1 car can out accelerate, and more importantly, corner at much higher speeds than any Le Mans vehicle.
An F1 car is quicker around the 'Ring and Le Mans, not just speculation, it is. This is the problem will people who don't know very much about racing dynamics, top speed is only one part of the entire package, not the most important part, which is handling dynamics.
Just do a search (I couldn't be bothered) and you will find a video of the F1 car going around the 'Ring with a time of 5:08 (and it isn't the quickest that car can do, either).
So just remeber, top speed isn't the only thing that is a deciding factor on a track like the 'Ring, or Le Mans, handling, acceleration, and braking power is much more important.