I wasn't on the car team so I don't have complete knowledge, but I believe the LOD 0 cars from FIII are what's used in-game now and that the interactive car bits in the garages us a new super LOD mesh. I could be completely wrong though.
Just got it. Doing the subcompact races. The AI seem more aggressive, borderline dickish. They keep spinning me out on Tsukuba. All in all looks great especially the new car shaders. Good job everyone. Can't wait to make something my own and race online. Maybe recreate my 2 second 0-60 golf ;)