importing users database from pnphpbb to vbulletin

[Jerry]

It will append "imported_" to the front so you will have "imported_abc" if they are the same user with the same email address merge on email during the import.

[Queen]

lets say i am running a forum with 20,000 members andi want to import some users db from another DB using impex.

lets say on that forum that i want to get / import user db from the name fx which is abc is also in my current forum, so what will impex do

likeif the nick abc is in the db which i want to import to vb , and that same nick is being used abc in my current forum, then what will impex do in such situatioN?