It depends on the stepping you get. You might get one that hits 3Ghz+ with no change in voltage or you might get one that only hits 2.6GHz with 1.6v. It's basicly a gamble.
noone can tell u how far u can overclock. i mean of course ur not gonna hit 6ghz on it but u could get anywhere between a 200mhz and 1ghz overclock. so just up fsb a tiny bit at a time. then test stability, then if its stable up the fsb again if its not stable up the vcore and just continue to do that till ur temps get too high