A little known fact. On the Porsche Carrera GT, Ferrari Enzo, and Lamborghini Muricelago and Diablo, this happens.
Ok, when these cars are sold in the US, they have Rev Limiters making it so these cars CAN NOT reach their top speed. The Carrera GT with a Rev Limiter will top out at 180MPH b/c of this on US roads. Now in Europe, these are not equiped.
BTW, the US Government issued this. I have asked Park Place Porsche, Lamborghini if Dallas, Aston Martin of Dallas, and Ferrari of Plano if this is true, Lamborghini, Porsche, and Ferrari said it was true. Aston Martin wasn't sure. Ferrari told me it may also be equppied on the 360 Challenge Stradale.