Replacement parts are out of this world expensive! Several months ago I broke a drive side crank arm on my XTR cranks.$220 just for the crank arm, no chainrings,hardware, or anything. Ended up putting the XTR's on a shelf and then bought a decent FSA set complete with BB for 2/3 the price of the single XTR crank arm. I guess XTR wasn't designed for the average Joe.
Just the other day I finally picked up a brand new XTR crank arm for like $40. Thanks ebay!