143 bclk, might need to go down 1 multi on your RAM if unstable, try it at the current voltage, if unstable add a LITTLE QPI voltage (1+ increment, maybe 2), you should be fine with vcore, and check for stability with Prime 95 26.3/26.4 I usually do about 9 hours.
2. Yes, you are right, overclocking from BIOS is better than with utilities
3. The best way is to raise the multiplier or FSB
4. Normal CPU idle is 40-50'C, full load 45-55'C. Do not get it above 65'C
5. It depend, stock cooler usually only can OCed by a little amount
6. It depend on multiplier, let say your multiplier is x10. Then you can set FSB to 300MHz, so 10x300=3000MHz=3.0GHz
7. Okay, that's a good specs.