An IP Filter won't work as well on dynamic IP's as static IP's, but it will help as dynamic IP's are usually rotated (there may be some casualties, but they can always get static).

The hashfilter will only work on known bad files, but still a large improvement. It will make the spammers and MAFIAA have to work even harder to mess up Limewire (Far to easy as it is right now)

The filesize filter will make them have to make larger bad files which in turn will need longer to download taking up their bandwidth and slots

All three together would give them a real headache