Seat time and experience.
Having your rig ready to go 6 months before the race (rather than having it finished 6 hours before loading it up) and running it is the best thing. Having experience, knowing its limitations. If I was ever going to run KOH, I would be out there a few months ahead of time, practicing. Knowing the terrain and knowing the obstacles, well, remember what G.I. Joe said, "Knowing is half the battle". I don't know a darn thing about west coast wheeling, so instead of applying what I know here, to out there, I would just go out there and find out beforehand.
REALLY good tires.
A lightweight rig so axles will last longer. Seems like the heavier rigs with heavy wheels and high output engines didn't fare too well in the axle department. Difficult to win when your axle is in shambles.
REALLY good pit crew. There was a video of Shannon Campbell with a flat. His crew was ready for him. Just craned (YES A CRANE) his rig up, pulled off the old tire, put on the new one. No time at all, just did it. REALLY helps.