First render I did in a looong time (a HD crash destroyed all my scenes some time ago ) It's got disturbing artifacts, don't know why. Going to have to get myself into it again.
The white bits (round the windows, the front lights, the side repeaters and although we cant see them, the trim round the rear lights.
To fix that you need to change one small part of your DDS file. When you open your XR_Interior1.dds file in Photoshop/Paint Shop Pro/<insert editing program here>, you will see a little white square with a black border. Paint the whole of that little square black, save and re-render.