I don't think your going too far with the stock cooler. And anyone here would advise against overclocking inside windows. You get much more accurate readings inside the Bios. The good news is you have a black edition, so you might get away with adjusting the multiplier a tad bit on stock volts. So the two main things to use for overclocking in your shoes would be the:
Base clock (fsb) and your CPU multiplier they are always labeled different
FSB x Multiplier = your cpu speed
But id recommend a cooler upgrade. Just to take the heat issue off the table.
One less thing...