just to tickle the other side...
the sport is rock cralwing, meaning slow. the vast majority of rollovers in this sport occur at slow speeds. jeeps go over all the time, even several rolls, and the stock roof holds up fine... kinda.
in rock crawling, a stock roof does a perfectly good job of protecting the passengers. thats it... but what about the vehicle, insurance will total it unless your willing to cut off the roof and weld another one on. and totaling your vehicles nets you less $$$ that what its truely worth.
I honestly feel that internal cages should be left to the desert racers and other high speed recreation. not only to protect the ocupants but for wind resistance even.
but in rock crawling, we build rock rails to protect our rocker panels, skid plates to protect our quater panels, and control arm mounts. bumpers to protect in case we get into an accident, so that we are not the ones stuck waiting for a towtruck.
then why build a, internal cage just to protect occupants in a vehicle roll. what about the poor jeep?
a properly designed and built exo cage will not only stregthen the jeep, but it will protect the jeep AND the occupants in the event of a rollover. but the are not dificult to get past when getting in and out of your jeep.