Changing Spark Plugs at 170k

You definitely qualify. I've been buying parts from my local Toyota dealer for years. Same two old Georgia boys in the parts department for that span. They've helped me out numerous times and I think they'd be able to verify if parts are fake as well as anyone on the planet. If you're saying that the counterfeits are so good that its impossible to tell, then surely the only place to buy parts would be through the dealer?

Since you're lingering in this thread since that is what you do... is your advice that I just buy coils from Rockauto (looks like $231 for 4)? Or should I just risk banking on the original 170k coils being fine? As mentioned, my worry is that if they're damaged in any way, I don't want to be stuck with a $400+ dealer bill or to be without a car for a few days. Seems like a reasonable concern.