overclocking limits 975x chipset

Depends on how high you can get the front side bus.
1066 FSB = 2.66GHz
1333 FSB= 3.33GHz

The 975X chipset in general is not a good overclocker, and you tend to need to pump voltage through it to be able to get a decent overclock. That said, 333MHz is likely to be attainable, but even that may not be possible depending on what voltage adjustments to CPU and NB voltage your board supports. The most I ever pushed on my old 975X board was 280 without being able to raise the voltage on the northbridge, using my E4400.

so will it be a challenge to get it to 3.0 on this.

why is the q6600 more popular than the q6700 will that change because of the new price for the q6700.

doesn't the 6700 oc easier
what are the advantages of the q6700?
what kind of cooling would i need for 3.0, 3.6, 4.0-with a new mobo?

will i be lucky to hit 3.4 with it even with liquid cooling (which i would get if i could go higher)