Jeremy clarkson gave an opinion which presents yet another thing to think about. If a car s limited to a certain speed then it only has to be engineered to cope at that speed i.e. brakes, suspension, tyres etc that can withstand 180kph or 250kph for example.
If a car is allowed to run to 200mph (around 320Kph) then the whole car will need to be engineered to hold up at those sorts of speeds.
Maybe its the law of dimishing returns?
Unfortunately I can't remember which episode of top gear he said that on, but I do remember that he was talking about why Mercedes chose to limit its CL cars to 155mph or something.