Sandro has excellent photos that basically shows typical configurations of both the nascar and the x style.

i have the nascar type on both sides and i think they go deeper into the door than Sandro is showing but that may just be perspective. mine go right up to the reinforcing bar in the door and you have to give a good slam to latch the door. i do not have as many cross braces as Sandro is showing. that looks quite well done.

with regards to the more bends, i think you need to look at how the hit takes place and what happens. i am not a structural engineer either but i know if if i put a 2x10 on its side, and i walk over it, it will bend a lot. if i put it on edge and walk on it, there is no deflection noticed.

when we bend a bar into the door, there is a lot of compressive forces that come into play when it is hit, for the x-bar, there is lot more tension forces taking place. i think the bent bars spread the force into the rest of the cage/hoop as well.

and for the extreme example, how much force would it take to "ben" a 1.5" bar that is 36" long when laying on its side vs. to compress it from its end?

now i will freely admit that i have no idea which is better at dissipating the force of impact to lessen the g's felt by the driver. Sandro's cage may be the best of both worlds. give up energy in all the space you can on the passenger side cause you can give up the space and lessen the g's felt by the driver. and where space is a major premium, you need the prevent intrusion on the driver side and know that you will feel more g's in the impact.

greg, thanks for a detailed description of what happened and let us know he was alright.