My E2180 went to 2.9ghz on stock volts. After that, it required 0.04 extra vcore per each 90 - 100mhz additional core speed -- very linear -- until it wanted 0.06 extra to go from 3.3 to 3.4ghz, when I decided that was enough. Happily running @ 3.25ghz 24/7 on 1.465v. With my Tuniq, a 21c ambient room temp, 4 case fans, good cable mgmt and an all aluminum case, idle temps are 24c and Orthos Blend temps are 58c.
3.2 ghz +/- 200mhz is the typical max core speed for most of these E2XXX chips before load temps & volts get too high. If I had to do it all again, I'd probably pick the E2160 given its consistently high OCs with less vcore than my E2180. But I'm splitting hairs here either way.