Everyone says tie it all to the frame, or body. Okay, now ask those same folks to diagram out how exactly your supposed to do that, and watch them act like they didn't see your post.
Adding hoops to the cage to tie in your seas raises the seats up an unacceptable amount unless your vertically challenged.
Think about how the structure of the Bronco is designed. 8 points attach the body to the frame. 4 of those points are in the front passenger area. 6 points typically attach a cage to the body, 4 of those are in the front passenger area.
Between those 4 points in the front passenger area that attach the body to the frame, are support channels running across under the floor pans.
Now, mounting a cage to the frame isn't exactly handy. I personally think it's a good idea and I hope to do that myself. (I'm currently ripping out floors to add good metal for seats/belts so I can install a cage.)
But I don't have an answer for what to do. I've asked for ideas here several times and I get confusing and contradicting information with little explanation that shows any engineering to it. The closest I've come is I talked at length with a Bronco cage vendor, and he pretty much went the opposite of what everyone here will tell you.
I will say, whatever cage you get, I think the best idea out there is a cage with complete hoops that cross the floor in the center of the vehicle. That way, cage tied in or not, if you roll, there is no way the cage can punch through and crush you into the floor. The hoop crossing the floor will hit the frame rails and stop.
What I think I'll do, is mount the seats and belts to whatever is handy, tie the cage to the frame best I can, drive carefully as I can, and try to not worry about it.
