The libraries are in ~/Library/Application Support , there is a 'FilterForge' and a 'FilterForge 2' folder there.
The downloaded filters are in System/Library in that FF directory, so I just copied all those to the FF 2 to get them there.
And for downloading, the trick to get them into the FF you want is pretty simple.
Have that FilterForge running when you click [Download this filter] on the web, and that FF instance will get the notification to pull it.
If you haven't it running, LaunchServices will launch the Last one it finds, (FF 2).
Cheers,
// Totte
- I never expected the Spanish inquisition