No you would still be cool because the latency as nubius, dj chris, and others will tell you doesn't affect you as much as you think. But even so you should be able to tighten up the timings at lower frequencies so I don't think it would do any harm.
I think 2 sets of the ram I linked ya will do just perfect.
And with a good heatsink I think you'll hit 2.5ghz no problem
I'm not sure about abit's overclocking abilities though. I'm hoping someone will reply to give some clarification on this. But if the abit board won't allow you to pump up the vcore very much then that would limit your overclocking. DFI may let you increase it more but I'm not sure. hopefully someone on this forum can tell us.