I never had a WT mod break anything.
The modders here are professionals that have been doing that work for ages and very often with the devs in mind.
e.g. The dude that makes the WT mod for Perverteers other game actually fixed bugs (not the first time) that are in the current release with his mod.
Honestly I'd never play a game with that many variables without proper WT. URM is nice but only necessary when there is no alternative. Also reading a var doesn't mean you know what it does.
Just don't download WT_mod.exe.zip and you're good...
By the way the schoolgirl patch doesn't do much, it only changes a few renders I think.