Usergroups/subscriptions from phpBB2
 

I've just bought myself a copy of vBulletin to replace a medium size forum but I am having a few difficulties with user groups and subscriptions.

I've got several thousdand users that I've imported over via Impex.

How do I mass assign these users in a user group of my choice?

Am I able to mass add users into a paid subscription? The site relies on a set of permissions based on a subscription.
I appreciate they will all have the same start date* but I will have manually set those myself as our phpBB uses a custom paid subscription solution.

Also* some users appear to be members of various user groups when viewed from the front end. In the admin control panel they are not members of these user groups. Any suggestions?

Thanks