I also wouldn't try to OC with the stock cooler. One of the problems is that the heatsink on the cooler for a second generation Core2 is half the size of a first gen heatsink. First gen stock heatsink was actually pretty good. I was able to run my Q6600 at 3.0 GHz. without overvolting the CPU.
For the second generation coolers, it seems that Intel made them no larger than they had to be.
So I will be able to OC Q9300 to 3GHz with the 1st gen stock cooler? Is the 1st gen Core2 the same as the P4 one? It will be nice if so as I can just stack with my old P4 HSF.