We have very seldom used suspension systems on any of our cars and we race on some tracks that most would consider too rough to be on.
With suspension you are adding some issues:
--more weight
--If done perfect stability and handling issues. I have seen rear wheel drive with suspension with too much travel start a harmonic motion that caused them to bounce and loose traction on the rear drive whee.
--If on the 'two wheel' axle and is has much movement then the car can lean out on tight corners which is of course not good.
--It one more thing to break and we go by the motto of 'Keep it simple-stupid' as if you break something you do not win
For driver comfort we make a seat like a hammock. We use some strong/light weight nylon close netting that has a folded 'loop' on the top and bottom that is then suspended by two tubes across the car. One is under the knees and the other is just below the shoulders. That way the driver does not hit things that are solid to cause pain.
We do still have a couple of tracks that just the shaking alone makes your body know it was in a race but no bruises or sore places.
If you look at PIX of some of our cars you can see these seats.
