Another thing I just thought of is that stock t-case manual transmission rigs should NOT be permitted. MT's gotta have crawler gears. AT's with stock low range are OK, but 2:1 low range is pitiful for hard-core rock-crawling. If you fry a clutch out there (which is highly likely), you're screwed.

Also, I believe that driver experience has a lot to do with how well one traverses the trail. An experienced driver in a stock rig will require less spotting than an inexperienced driver in a modified rig. Self-spotting is key to a successful, efficient run, especially in large groups.

At goneMOAB '03 I ran Golden Spike with something like 20 rigs, some with just a lift and inexperienced drivers. It took well over 12 hours before we hit the pavement again. There were many times were we'd be backed up for 15-30 minutes, waiting for a stock rig to get unstuck because the driver took a bad line. Those delays really add up.

The Rubicon isn't like anything Nissans have run at Moab. In Moab, there aren't giant marbles that can roll under critical drivetrain parts as you drive over them. You have to know how to drive on moveable terrain.

Finally, many (actually most) serious Jeep 4-wheelers are used to bringing lots of spare parts and know what stuff breaks often. They often carry parts like axles, brake lines, driveshafts, U-joints, hubs, gear oil, coolant, etc. Most Nissan 4-wheelers I know don't carry a spare drivetrain around with them; Nissan parts are expensive!