Best method to test and upgrade etc?

[Gimmick]

Hi my forum is now stable and getting members, there are so many mods, and styles I want to play with but dont want to take the forum off, or cause an errer.

What is the best and legal method (licensiing) to do this?

Thanks

[Dismounted]

If you have a valid Software license, you may set up an additional test forum in order to test code, template and database modifications. To make this clear to us and our license verification procedures, place it in a directory called 'testvb' and be sure to password protect it. It must not be accessible by the general public.
http://www.vbulletin.com/order/license_agreement.php