Lions back? No problem, it's closed now. But the tractor trailer - even if the cage held, the sudden stop and direction reversal would get you.
It can only do so much.
If that's installed it sounds reasonable.
About 4 feet of tube @ $3.00/foot, 2 bends and 2 fishmouths. 1/2 hr making it, another 1/2 hr welding it in.
When they do it, make sure you have whatever top you use on it. Not fun to find out later the top "almost but not quite fits."
Unless someone is really tall in the back seat they usually have room above their head under the top.
Seems like I've seen pre-made bars that go across the back corners - some weld-in, some bolt-in.
Check OR FAB, Poison Spyder etc.