Well because they removed all the hidden car bodies (even the sample ones and the us F1 cars) from the Pal version of GT3. I can drive the diablo porche stratos etc, but they will have a Daihatsu body.
BTW when I try and change the colour of the 911 it remains white, also when I view the outsde view of the car it is elevated so you can just about see the nose of the car.