as for moving the data, it is actually pretty simple, thing is ... if you are willing to rearrange 350664 Posts within 49236 Topics from 37469 registered members into the categories of the new forum, I will be more than happy to pass the task over to you guys.
I will do it, that is one of the things a computer can handle, now which forum system are you moving to so I can start to prepare, and when can I expect a copy of the data
not joking (I may not be successful but I will at least try my best, and I have moved a forum nearly as large over 4 systems to get from A to B with a rotten database)