Haha, I'm looking at XF now as well, looking to see if a developer that knows GT forum, might be able to help the import. Maybe even if a few us us get together to help $upport their effort.

Looking at the XF boards they also have some premade importers which might make it easier to leap frog GT into one of those other boards, then into XF

http://xenforo.com/community/threads/pre-sales-faq.4951/

Does GT do custom work anymore? Maybe one of the guys that really knows GT would be able to help.