You're getting confused dude, not every single 144 processor is going to overclock exactly the same...depends on speedbinning, fab location, stepping number etc.
Basically, the CANBE stepping cores are the absolute best you can get, they're the ones they have been hitting 3GHz on air with almost no vcore change...you won't find any CANBEs anymore though as they were the first batch
Next in line would probably be the CANYE stepping cores, these have also been hitting 3GHz but with much more vcore neccesary
Basically all I'm saying is if you're thinking that you're 100% guranteed you're going to get a monster overclocker, you're going to be in for a nasty shock as every single core is engineered differently and its entirely luck of the draw
If you want good results though, I suggest you order one NOW as is what I am doing...overclockability trends from AMD has traditionally degraded the longer a core has been availible due to tighter speedbinning and perfection of manufacturing