I can answer the first one: When youu overclock your Front side bus IE. 105 mhz or 110 mhz. you are overclocking your whole system, not just your processor. unless you have a unlocked processor and are just changing the multiplier to a higher one.
So yes, when you run them out of spec IE overclocking you can damage the data. As for the devices I don't know what effect it would have on them. other than maybe not lasting the time that the manufacturer says it should last