[quote name='BlueScrote']I have a feeling that is going to go poorly causing you to rage quite bg2.[/QUOTE]
Negatory.
The mod in question is called "Happy Mod", and it is part of the BG2 tweakpack. I already had a bunch of tweakpack stuff running, but I wanted to add on Happy Mod (or a variant of it, at least) now that I have Viconia in my party.
The game has a "reputation" system with various minor effects. High reputation (being a good guy in quests) will get you discounts, low reputation (killing people, being an asshole, transforming into on of the avatars of Bhaal, God of Murder, etc.) will get you bounty hunters. However, extremely low reputations will cause "good" party members to leave you and extremely high reputations will also cause "evil" party members to leave. This kinda sorta makes sense, but...
1: Viconia is a new addition to the party. I already had maxed out reputation when I picked her up. Having her be all, "Hey, paladin guy! I want your dick!" one moment and then totally disgusted and taking off a minute later doesn't make much sense.
2: Some of the alignments in the game are screwy. Viconia is listed as evil, but she acts neutral. Jaheira is listed as neutral, but she acts good. Korgan is listed as chaotic, but he actus neutral. A lot of NPCs have really screwy alignments, too, which messes with "extra damage against/protection from X alignment" stuff.
But the freshly installed Happy Mod is kinda-sorta working. And if it doesn't, I'll try going back to my save from just before I added Viconia and work from there.
EDIT: And despite my frustrations with the ruleset and general mechanics behind the game, it's still got Bioware's best writing. And some of their best voice acting, too. Damn, Jaheira.