I have their cage in my Rubicon. Nice cage! Nope, never needed it <knock on wood>
The only suggestion/tip I have for you is to make sure it is square before you tighten anything. If it's not square and you tighten it up, it WILL distort everything and pull it around. And work from the front back... IE do the dash stuff, then the over head driver stuff, then rear seat stuff.
Edit: Oh, and always drive your rig with the windsheild frame attached to the cage and the bolt on the side of the frame itself! The windsheild frame acts as a stiffener. I've seen others fold up because the windshield wasn't bolted to the cage, not sure if this would but no sense in testing THAT feature...
Also, I couldn't use the two inner bolts, or at least they were difficult to use. So I delted them and only used the two outers and the two on the fenders. Make sense?