Some will be ringers and might have had the RS Turbos plates and floor no swapped. However the roof drain gutters run right round to the boot lid on an RS shell, whereas on base model and XR shells it stops about 2cm shorter.
Yeah thats interesting to know. When I think about the roof gutters on mine they do run right to the back near the bootlid. You know how on the RS turbo's there is a little flap on the floor down the side of the drivers seat and when you life the flap it reveals the VIN number or identifier. Does the MK4 XR3i's have this same flap as well??