I've heard rumors that their alignments can be changed to good during ToB. Now as I've never taken Sarevok along (I just don't trust him) and always romanced Viconia when I was evil myself I'm curious. Is any of that true? If so I'd greatly like to start a new game with Viconia as my love interest and convert them both to the good side.

don't know about Sarevok, but Viconia is for real as long as you're romancing her. however, I don't know whether it can be done if your PC himself is evil (what's the point? it makes more sense if your PC is good and so converts Viconia to good).

IIRC, Sarevok can be changed.

It's easy to miss the conversions, though, if you speed through the game and your decisions are less than precise. ;)

I've managed to convert Sarevok to a good alignment (Chaotic Good I think...).

Just take your time with his dialogue options and don't rush through the game.

okeydokey
please don't spoil me on how to convert the two, I just wanted to know if it was possible