Like Acill said, we beat them up pretty good down here at SDRC and other tracks in the area. While we're very pleased with the durability, it is not indestructable and parts do eventually wear out.

Normal wear items to have on hand (no particular order):
hinge pin inserts
rod ends
bumpers
spur gears (composite, rare to strip one, but they eventually wear)
shock o-rings (regular / normal maintenance required)
diff rebuild stuff (o-rings, seals, case, regular / normal maintenance required)
the rear outdrives wear a little faster due to the dog bone sweep, but nothing abnormal
shock bushings (the part inside the shock cap eyelet that fits the shock standoff)
Rear center shaft pins wear eventually. Front dog bone may wobble if you repeatedly lawn dart, but they have been pleasantly trouble free.

Things that commonly brake on other cars but NEVER broke during testing:
rear hubs
steering blocks
spindle carriers
bulkheads
drive shafts (bent a couple)
wing mount (deformed a little, but never broke)
A bunch of other stuff never broke

Parts that we broke/damaged during testing (no particular order):
*rear arm (3 broken in 9 months among 7 test cars), 0 production rear arms broken.
*front arm (~10 broken in 9 months among 7 test cars), most of those were not the production material (only 2 broken production arms), every arm break was a major crash, like straight into a pipe or dropping 15ft out of the air right onto the arm. We feel other cars would not have survived these crashes either and we walked away from a lot of crashes we felt other cars would have broken from. Keep some handy like you would with other cars.
*we bent some front shock towers early on, but have since updated to 6mm thick 7075 aluminum, no issues now.
*shock shafts (3-4 broken in 9 months among 7 test cars)
*We had some issues early on with our hinge pin braces. We redesigned them and produced them from 7075 aluminum and not a single issue since.
*We're all still running the same chassis we started with. They wear eventually, but they sure are lasting a long time.
*we bent 1 inner hinge pin and 1 rear outer hinge pin in 9 months.

We will probably post this report on our website soon as well.