Well i have been working on this for a few weeks, trying a lot of diferent setuos for the wheel colliders and suspension, now it seems to work well.
My objetive is to make a kind of sand box racing game, where you can place obstacles, ramps and other stuff on the track and then drive arround with a friend.
Video:
On the video the car in controlled with the mouse and sincronic shifting.
(sorry for any error, english is not my natural lenguage)