The following statement is just my professional opinion. So please reguard any info you don't like as SPOBI.
Alright I have been in to Collision Repair field for 9 years. I specialize in unibody structure. And I feel that I have enough experience to voice MY OPINION on the doorless thing.
Your doors are ONLY structural in HIGH impact sitituations. As in moderate speed frontal offset impacts with speeds of 35+mph. You ever watch the NTSB and Insurance board offset frontal impact at 35mph videos. You will see that your doors are structural. Infact there are laws that state the OEM doors, as well as 85% of the windshield MUST remain closed and intact at the 35mph offset frontal impact. (97 to present)
Now offroad unless you are seriously flogging(rolling) your rig you WON'T twist the unibody. And if your flogging it, you probably don't care if your unibody is twisted anyway. The unibody resists twisting hell of alot more then any OEM framed rig. I can take a framed rig and turn it into a pretzel with a pair of 10 ton frame towers. A unibody would tear long before it twisted. Infact I have seen many framed rigs twisted and diamonded, but I can never remember a single unibody that was twisted and diamonded.
So to sum it up. The only time I would worry is when your on the street, you never know which driver going the opposite way could cross the yellow line :skull1: Your doors could be the difference between a trip to the ICU and a trip to the morge. It is your call. Go ahead go doorless, I plan to, just know the consequences.
Hans