Question on sure grip parts

I'm not sure if I would worry about a "chip". It kindof depends on how big and where said chip is, and if you are road-racing the car, or if she's just a streetier.
The only time the spiders rotate is when going around turns.......... unless of course,you peg-leg them. And going around turns, usually means your engine is way down the power curve. So those spider gears can look really really sad, and you'd never know it until you look at them.
Plus; the spider gears and side gears wear as a set. If you replace just the one part, it will be carrying most of the load for thousands of miles.