You could lower the friction on the supsension, probably makes it less twitchy.
And make some stops so the supsension doesnt fall out.
But drives pretty good. Could try to tweak it so the wheels stay on the ground more.
You could also read what has been typed in the boxxes and try to find out how it works. (the boxxes found under menu item "script menu").
When you know you dont have to ask anymore. It's called learning.