This is what I've found in relation to the WTC Mod for GTA IV:
However the older versions (1.0.0.4 included and older) need a patch to be installed to avoid critical crashes while game loading.
The version 1.0.0.4 is mandatory or the game will crash when it will be in the loading phase. You'll want to avoid that, that's why it's needed to update the game to that version.
