The new option to remove the driver seat / headrest is a great idea! However, I noticed it doesn't seem to work in the DTM 2016 Audi RS5. Also someone mentioned here that the AMG GT3 has the same issue. I'm guessing some cars were either forgotten, or there are some car models where it wasn't as easy to separate the seat from the rest of the interior 3D model. Hopefully this can get addressed in a future update.