You've go some high end stuff there so i would recommend getting rid of the stock cooling and get liquid and then "FILL YA BOOTS" as they say.
O/C a system of that spec should be a doddle.
Stock volts and up the multiplier.
See what you get, keep an eye on temps at all times when your o/c ing.
That's to start, but once you start you can't stop... it's like a drug.
You have to go faster, just a few more points, just a little more voltage, just make it colder.lol
I laugh but those that o/c regularly that are reading this post know i'm not joking.
You will find yourself sitting in your room with all the windows open and the ambient temperature around 9-10C, hat and gloves at the ready but you don't care because you just got an extra 200 points in 3DMark06.
But i personally wouldn't have it any other way.