Well, it shouldn't be a surprise then, to see what it looks like where the back of the factory cage goes down through the inner fender.
Oh, it doesn't go anywhere, it just stops.
Here's what's under it.
As shitty as that looks, we can still learn something from it.
*It's sandwiched on both sides. Making it three pieces thick where the load hits.
*The bottom ties into a vertical piece of metal.
*In the first pic, the indentation creates vertical portions of metal, increasing resistance to bending.
*Wrapping around the corner gets into a long run of vertical metal, adding strength
*Tying into metal on multiple planes is a good thing.
And with all that engineering, I could still move the ends of those bars a few inches in any direction, before I cut the spot welds. It still had a lot of give.