Strap another fan on that cooler in a push pull and you are in the 4 gigz no sweat. Just because it's not 80 bucks doesn't mean it isn't AWESOME.
If you DO get bored and look at pushing the throttles forward a bit more, get bored with AS5 too and take a look at some new paste. Also, grab another 120x120x25 fan and use the supplied bracket to put it on. As for what kind of fan? Well, that's another conversation! That'll keep you in the same temp ranges (remember, your AS5 will cure in about 200 hours or so and your temps will drop beyond that) and yet give you room to improve performance even on the stock cooler.
Additionally, if your clock is stable, then you could consider re-enabling some of those power saving features- that will help prevent your CPU from running at that clock all the time.
Thanks for everyone's help!