Interesting. The only damage I've seen on a cam gear was where someone tried to remove a flywheel and attempted to lock the engine with a big screwdriver between two cam gear teeth. Both failed, ouch... That makes sense. There are people who rally V4s to the max and swear by fibre, others use steel gears on road engines. Great info on the balance shaft weights, I've been meaning to weigh a few for ages, just never got around to doing it.