it should be be fine after some good ol' overclocking, id say a 3.2GHz or 3.3GHz overclock should be fine and if your mobo is a good overclocker you can get to those speeds without any voltage changes. i have the same cpu and as soon as my arctic cooler freezer 7 pro hsf arrives, this Q9300 is going for 3.5 or 3.6GHz
it should be fine, i cant really say what volts will get you where. the mobo i have (Evga 780i SLI) i can leave the volt settings on auto and raise the fsb up and it will do the volts for me. from the reviews i read, the Q9300 can reach 3.33GHz without changing any volts. so make 3.33GHz your first goal, then if you can reach that without changing any volts your good. but anything after 3.33GHz you will need to adjust the volts. and i dont know the overclocking ability of your mobo so reaching 3.33GHz without any volt changes might not work for you as it does for me. it depends on how well the mobo handles things. the 780i SLI mobo is an extreme enthusiast board.