You do not need to think abourt weight unless you are using fan power. As long as it is not so heavy that it puts pressure on your wheel bearings it is fine.

You can use as many wheels as you want, although I would not recommend using them as you want your car to be as skinny as possible in order to fit inside the smallest bonus gap.

Does anybody have any practice test links they can give me? I cannot find any tests for this event.

My battery buggy does not run straight all the time. I am thinking this is because the wheels have an apparent "wobble" to them. Does anyone know how to fix this?
I am using Banebots T-81s on a threaded rod axle.