How do I convert multiple Subscribers to Supporters?

I have a group of users / blog admins who have been acting as my "beta testers" while I was learning the basics of using WPMU. As a "reward," they have been allowed access to all features, including those that will be reserved for paid "Supporters."

Now that I feel confident enough to start marketing my site, I would like to change the settings of what will become my "Premium Plugins" and I am not sure if this will remove access to these plugins from my beta testers.

Do I need to upgrade these users to "Supporter" status in order for them to retain the access they have had, or will they retain that access when I change the plugin availabilty from "Anyone" to "Supporters?"

Also, what is the difference between "Supporters" and "Supporters (auto-activate)?"