There's no boundaries if you're bold. However, this site isn't overclocker-oriented, so don't be surprised if someone says "be afraid of high voltages. blah blah blah." I've seen 1 or 2 overclocks about 4Ghz on that cpu on air cooling at evga.com & an overclocking forum.
The weakest link in your specs would be the psu. It might give out if it's crap.
There are 2 steppings. 62.2C VS 71C. Keep it 5C less than max under load. Use cpuz to find out about yours. Or look at the cpu box for the sSpec Number in the URL.http://processorfinder.intel.com/details.aspx?sSpec=SL9UMhttp://processorfinder.intel.com/details.aspx?sSpec=SLACR