bill,

there are alot of good comments on what to bring. the actual enduro is the easy stuff...the prep work in the shop is most important. below are a few things we do at the shop to make sure we are at the finish. tools and crew aside, think of things that will put you out of the race altogether...you can't win if you don't finish. a few things to consider:

keep things simple and clean:
keep your engine bay clean so if something goes wrong you can identify and fix the problem right away. it's tough if there is crud and dirt everywhere...AND everything is hot. look for any rusted old bolts and replace, nothing worse than having to fix something and you can't get the old part off or a bolt breaks. if your running additional lights, wire everything and secure all connections...make sure the fuses and relay are easily to get to if there is a problem. we try and color code additional electrical so it is easy to find/follow/fix. check all of your ground wires for EVERYTHING and make sure they are tight...bad grounds shut you down and is the last thing you think of. you get the idea... be ready to fix everything if it goes wrong, you may have a few people not familiar with your car so make if easy on them.

spares:
if you don't finish you can't win, replace all of the normal stuff before the race as stated in the posts. what parts can break and keep you out of the race??
spares list:
radiator
MC
alternator
alternator belts
calipers frt/rear
brake lines (may go off road and cut/pinch/splice)
rotors
pads (a few sets)
hubs
tie rods
knuckles ( we pre assemble with caliper/pads/rotor so if we need to replace we don't have to pull everything, just replace it all as one piece)
axles
cap and rotors
ignition coil
plug wires
lug nuts
shocks
these are just a few things to consider.

we like to locate and get open hours for the nearest windshield shop just in case...can't run with a busted windshield if you roll. there will be a few drivers in the car during the race and things can and will happen...have some BIG tools and prybars to pull or bend out any major damage. we have had a few incidents that looked to put us out of the race but we had everything we needed to finish...it didn't look good but we were there at the end. hope this helps...can't give up all of our secrets though.

~jay