Min/Max Contact Settings
It is not required, but highly recommended to set your Physics Contact Offset settings as low as Unreal will allow you.
The default settings will cause your wheels to bounce when moving between separate surfaces as if it hit a bump, even when they are at the exact same height. This effect gets worse the higher your movement speed.
Max Terminal and Angular Velocities
These settings will limit the max speed of your vehicles. I recommend these values:
Default Terminal Velocity: 7600
Max Angular Velocity: 10000
That should be it! The Vehicle System should internally take care of any other settings where possible.