Importing into TMG via GenBridge has absolutely no affect whatsoever on your original database, UFT, or any other GenBridgeable (is that a pronoun?) database. A backup in the original program is recommended of course.
I have had TMG 4.0a for less than a week but have imported and deleted a GenBridged (is that a verb?) .pro three times. I expect to do so again and again this month.