So we figured out that by halving the weight of the tire nodes (just the tire nodes) and reducing spring and damp accordingly, we solve a lot of problems. The vibrating wheel problem when powered is pretty much gone, everything is smoother, the grip is sharper and better, top speeds are a little higher, and things are more stable and fun to drive. Basically we’ve reduced the gyroscopic forces on the wheels to a realistic level and everything is better.
So yeah. Coming soon in a patch.
EDIT: We tested with 900 degree steering wheels and confirmed that the numb/sliding problem is practically solved. It feels quite good with a wheel now, even without force feedback.