Hello!
In Unity 4.6 I could pretty much take away all sideways skidding(friction) by increasing sideways stiffness to 10000, but in Unity 5.0 that makes the car go bonkers.
What would reduce sideways skidding?
Increase the stiffness value at the very bottom of the sideways friction. The stiffness value is a multiplier for all of the sideways friction values above it. Decrease the sideways friction stiffness, and your car will slide like it’s on ice. Increase it, and it may corner better but it could also flip due to too much friction. The same principle applies for forward friction. Also, friction is the opposite of skidding. The more friction, the less skid. For a racing game I am making, a sideways and forward friction stiffness value of 2 works fine.