Help OCing my E2160

[jaqu]

Hi, i need a little advice from the pro OCers.
I clocked my E2160 to 2.88 GHz (couldn't go any higher and retain stability), default Intel cooler, default voltage, and 320 MHz FSB. All I did was up the FSB, and lower the memory multiplier. I ran it like that for about a month.
Now I recently got a Asus Silent Knight 2 cooler, and now I'm upping the voltage to hopefully go a bit further up the MHz tree.
I just want to know, how high can I make my CPU voltage before frying it? My mobo (Intel G31 chipset) can up it to 1.56 or something, but I'm sure I'll be shopping for a new chip before it actually gets that high?
Anyway, before I started upping the volage, I lost stability when my Memory's FSB reached about 960.
Now since I started upping the voltage, I have only reached 3.01 Ghz and it is hardly stable, my voltage is on about 1.38 now (al the way from 1.325). My memory FSB is only about 850 or so.
What is causing the instability? The memory FSB should be able to go up more, do I need more volts on my CPU? How far can I go? Temperature is not a problem at all, CPU is still not going over 45 degrees celcius on peak.
I hope i didnt leave out any info.

Thanks in advance.