You've got a point there on PMs... In .C we could restrict users abilities to edit the profile; i think that'd be a good way to enforce this, but it's not presant in .T7 lol...
As for the install/import; basically you'd make a new directory (ubb7 for example) and install threads there; then you'd do your import, and once completed you'd delete your ubb directory (which is likely your UBB.C data directory) and rename your new directory (ubb7) to that (ubb).
THe importer for UBB7 comes with "redirectors" which will redirect requests to your old forums to the new locations; the non-cgi copy can go in your UBB7 directory if it's using the classic non-cgi folder (I have this on my forums)
