Very good. 8/10. I think the suspension breaks a little to easily. And about your suspension problem, the way I do suspension and keep real weight is by double-clicking the spring strength bar and typing in a higher spring strength, like 3.00 or 5.00.
It worked when I downloaded it this time. Very good! It looks like the engine should have its springs damping at minus. And after studying this scene, I learned a better way to make gears for a spring engine! Thanks! This is a 10/10.