Hi Ken.

I would like to ask, is the steering servos linear in control or just like ON-OFF switch?

I mean can you control the amount of turn, or the angle that the car will turn? Or is it full right, full left and center?

Also I cannot see if you really have speed control over the car. It seems that it accelerates fully in every direction.

Anyway, sure it is very nervous in reactions. I will repeat my self and tell you to have a look at PID control. It is the only way to have smooth control of the speed and steering.

Ioannis