How to go about setting up unique car system?

Hello. Lately I have been working on a project similar to games like Crossout or Robocraft, and have simulated their building systems. I got the physics and building to work. However, I am not sure about how to go about making the vehicle move. A sample of my system is shown below:

It can be seen that I got the car to accelerate forward, but this was by only applying a continuous impulse in the forward direction of the car. I want to go about making the car move, well, like a car. The standard vehicle movement systems wont support this type of car (to my knowledge) because the amount of wheels can change from vehicle to vehicle.

To get more in depth about how the vehicle works, the first frame of the car placed is marked as the parent. All further pieces placed are attached to the parent piece. When I want the car to simulate physics, I enable physics on only the parent so that the child pieces follow suit. The wheels are unique, as they have suspension, so I constrained them to the parent body so that they could properly simulate suspension.

What should I do in order to create this car system? Any suggestions are appreciated.

Thanks in advance.