[PvK]

Hmm, a difficult question. You'd of course want to be sure to keep any racial tech areas. I don't think you'd want to change the research order, or the ship designs. Offhand I'd think the main issue outside the AI_General file would be the design construction AI file, which determines how many of a ship to build, because if the AI has lower resource or maintenance reduction values, it may not be able to afford as many as it could before. I'd only expect that to be an issue for TDM modpack races which were highly tweaked in that regard, and/or that took heavy advantage of the cheap maintenance reduction in the unmodded game.

I'd actually think the unmodded AI's would tend to be better off in Balance mod than the TDM ones, inasmuch as the unmodded ones weren't very well optimized, so they'll benefit from the Balance mod giving them balanced value for points. I expect the existing TDM races take a lot of advantage of the unbalanced unmodded empire costs, so they'll be in worse shape, relatively speaking. All the more reason to work with those files if one were to make custom AI's for the balance mod.

PvK