I faced the issue that AI cars start jumping around when wheel to wheel position. When some distance between cars everything is ok, but when opponents car is inside some radius around players car - it start jumping back and forth. As I found from test - it does not depend on car. But looks like depends on track. Portland is less prone to it. But for example Laguna Seca and Nurburgring are. Here is video what I'm talking about. When measuring FPS with fpsVR it shows stable 50-60 fps without any strange spikes during such opponent jumping. I was not playing rFactor for some time so I can't confirm that it was not there before. If some options can influence it - let me know.