Is the ferrare the fastest car?

Before asking something like that one has to define whether it's a car straight off the dealer's floor, or if it's a modified car you're talking about, and in how many examples the car has been built. I believe that the fastest car straight off the floor in something like serial production is the Bugatti Veyron, which does 400 km/h (250MPH), but there might be other modified cars that are faster.