LJ body flex w/o roll bar? Is it really *that* bad?

[Tech11]

I recently installed a gr8tops half hardtop. Which meant cutting the rear "kickers" off the roll cage.
My plan is to go with either a rock hard or or fab sport cage for the cab, but as far as the back goes I'm not really sure what I'm going to do.
Gr8tops website says:

The unlimiteds almost require that the rear cage be reattached or a new external cage fabricated.
The body and the frame on the unlimiteds is much longer and therefore will flex more in off road conditions and could possibly warp or bend body panels without the rear bars installed.

Now I have seen loads of LJs with this top with no rear roll bar offroad and I don't see the body folding or snapping in half. I do however see some that have full corners which I guess would strengthen the body up some.
I was toying with the idea of bed rails like this person did:

And maybe building on it, having a cross bar connecting the left and right sides up against the rear of the bulkhead/top.
Then again I could get a rear roll bar/sport bar in the back like this:

IS there really that much body flex? Would the bed rails like above prevent it? Or should I go with the roll/sport bars in the back?
My plans are to not go buck ass wild with quadrangulated super flex a mighty suspension 5000, mega tubed out wall crawler or anything like that.
My plans are to do a Hi-Line kit, upgrade all the control arms, a 1.25" BL/MML, tummy tucker, and run 33/34" tires.

 

[wrangler00]

if it was me i would do the bottoom one because there would be alot of pressure on that back half and a roll bar is a cool and pretty easy fix for that kinda problem better safe than sorry better to spend maybe 125 to build a roll bar than however much it is to replace the tub on a unlimited

 

[35xj]

where did you find the pics of the black jeep/truck? any more pics?

 

[Tech11]

gr8tops.com website. And 125 for the roll/sport cage? I was thinking it'd be more.