U still didn't address my question. How exactly was it failing?
All the things you mentioned (wires, plugs, PCV valve, ect. ) wouldn't necessarily do anything to the SC. If anything, it would do damage to the engine first. Some of the possible ways you can damage the SC is starve it of lubricating oil, over spin it with a smaller pulley or have debris get lodged into the housing.
As for the warranty, you're outta luck after 60K. Upgrading to an extended warranty might cover it. Get it in writing!