I'm sure that things can be done to vastly increase the safety of a rally car.
What about a nerf bar style doorbar? This would add needed triangulation that the nascar style door bar does not have. With the angular point of the nerf bar style door bar being at the same point horizontally as the occupants torso / hips.
For the roof halo structure a diamond shape triangulation with the points of the diamond lining up with the occupants torso / head area when viewed from above.
Thoughts?
I need some good physics software...