[Xorlev]

From what I've been reading, the Sphinx addon doesn't have the ability to search for posts by user, right? And the only way is to make a new field for a fulltext index?

Well, I'm not sure about Sphinx 0.9.7, but on my own (not vBulletin) site running Sphinx 0.9.8 I was able to replicate every feature of the vBulletin search and then some using only the API calls in the Sphinx PHP API. If someone could summarize what's missing in the vB Sphinx implementation I could possibly help write in the features missing. It really takes some experience to be able to work with Sphinx, the documentation is rather lacking.