From my experience you can move threads from one forum to another and vice versa without any problem... (that is, ofcourse, if you don't keep a copy of the moved thread in your source forum)

Quote
I've been looking to upgrade to the latest stable version, but I've been reluctant to do so since it's got your spider hack in it and I know it'd
get bopped without PHP acceleration.
You can disable Spider hack from the control panel, if you wish. <img src="https://www.ubbcentral.com/boards/images/graemlins/smile.gif" alt="" />