You know what you're doing biut I don't envy you that changeover. Keep us informed as to when you'll be doing it - will the website be off line for a while? It will be missed if it is.
All the work that will be done is in the background, when we actually move to the new software, this forum should hopefully only be unavailable for 30mins max.
It won't happen for a few months, I've first got to wait for SMF2 RC2 to be released and I'll then start ripping it apart readying it for the switch.