The mods are for class, race, and diety to modify faction based on those. There are a few good writeups on faction here in the forums. Just do a search on faction and look for the message titles sound like they are for what you are looking for. I found them pretty easilly that way. There is also one somewhere that talks about what faction level for the various con levels but can't remember where it was offhand. But found it by searching faction as well.
Hope that helps..
