Want overclocking help? The best thing to do is to register here:www.short-media.com/forum
I'm one of the mods over there, and we've got a dedicated overclocking forum... we'll be able to help you out.
Also, Vantec what? There are no high performance Vantec heatsinks; they simply don't exist. If you want performance, there's really only one choice right now: Thermalright.
A SLK-800, SLK-900, SLK-947, or SP-97 will handle that 2800 without a problem. Arctic Silver's effectiveness is questionable at best; I use their Ceramique, but mainly because in theory it's better and it's dirt cheap. But going out and buying AS5 is just plain stupid, as it's performance is marginally better than regular compound at best, and as far as I know, no one to date has done a valid comparison between the two, so...
Anyhow, navigate your way over there and we'll give you a hand. And in case you're curious, my 1800+ is in an NF7-S 2.0 and does 2.6GHz on air cooling.