I personally prefer vBulletin over any forum.
After googling, I've found a link;
http://www.vbulletin.org/forum/showthread.php?t=249277
I assume you have mod access.
If not, I have a legit vBulletin license.
I've attempted to convert many forums, some with success, some with minor issues, I don't like converting forums as it makes feel the forum is UNSTABLE.
Example, I converted a phpBB to IPB and made all "Registered Users" full admins and made all "Admins" registered users. What can I say, times need to change for have 10k+ admins? Lol and 5 registered users. (A simple fix, correct this issues.) but also had few posting issues.
Now keep in mind this was like 4 to 5 years ago, so I assume the bugs are all worked out.
but, I don't see any reason to change, Unless this is a "NULLED" version (Not saying it is) - but "IF IT IS" and you decide to stay on it, I recommend ordering it and it's very easy to upgrade to 'NULLED' to 'LEGIT' (Done it few times for clients, Go figure - They had a DMCA complaint, therefore they were forced to buy it.) 2 Clients done this;