This is the one part of vbulletin that I absolutely hate. Almost any forum you go to that is powered by vbulletin will give you horrible search results.

There are two options available, neither of them seem to be worth a damn as far as I am concerned.

How can you refined this feature? Is is possible? Is there a quality hack/mod out there to fix this?

vbulletin search

Are you wanting more relevant results or quicker results? The quicker results can be had through this hack: Sphinx Search - vBulletin.org Forum

as far as more relevant not sure if the Sphinx deal tackles that. If not then I don't really know of anything else

Looking for more relevant searches.

I assume you're already using fulltext searching?

Yeah, using fulltext.