It's hit and miss. I've re-installed IV an unimaginable amount of times, and I always install the same mods however, some fresh installs with the mods I can play for a good hour, and other installs, I crash on the loading screen or 5 minutes into playing. Like CRAWFORD said, mods are VERY difficult in terms of compatibility. I myself use Abraxa's mods (coroner, towing, policehelper) and rarely crash due to those.
There is more chance of someone releasing a similar mod then update those in question.
All I can suggest is, if you scripts mods do crash whilst in game and don't crash you game, press " ' " or sometimes " ` " and write, "reloadscripts". This will restart scripts, fixing most errors and you'll just have to simply start the mods up again.