on the overclock.net boards , people are getting 2.5ghz stable on air 24/7 . with water ive seen 2.7 with a good chip . I would say 2.3 is all you will get stable without some vcore added .
As far as HTT goes you have to try to keep it as close to 1000 as possible , my htt becomes unstable @ 1080 so their is some wiggle room . Say your running a 250fsb , your htt should be set @ 800 or 4X . 4x250 = 1000htt . I'm guessing your @ 230X10 for 2300mhz? 230X5 = 1150htt , that will prolly cause stability problems under prime95 after 8 or so hours .
Is that @ 1.4 vcore stock? Ive ran mine up to 1.6v on water , on air i wouldnt go over 1.525V , your temps really dictate how far you can go , some chip are better than others . Mine runs (265X11) 2915mhz 24/7 from 2200mhz with only 1.5v and (273X11) 3003mhz with 1.55v , so you might get lucky and not need to go very far.
Other things you might have to do are, lossen your memory timings when the fsb gets higher , that depends on how good your ram is. With my corsair xms it needed vdimm voltage at anything over 220 fsb, corsair defaults to 2.65v , but likes 2.85 for higher fsb's. You might come to the point where you need the memory divider to keep the fsb on the cpu high , but run your ram down closer to spec . 38
