If your iTunes music is just coming from your LW downloads, it will be saved where it always is (in LW library, click on saved files then click explore - will show you where your saved music is). If you've added other music outside of LW, I'm not too sure.

To be on the safe side, you could copy everything to a different folder outside of iTunes. That way, if it does disappear, you can add it back into iTunes when you reinstall the software

Good luck!