Is it normal to hear the soft top shifting while it is up when you drive over a bump?
For me, the excessive shifting was caused by a stripped fastener securing the latch mechanism housing to the windshield frame.
If this is the case:
Here's a link on how to remove the roof latch housing:
http://www.renntech.org/forums/index.php?showtopic=4230&view=findpost&p=20543
Here's a link on how I fix mine with tools not normally available at the neighborhood Home Depot:
convertible top latch
Some more reference:
http://www.flat-6.net/forum/showthread.php?t=14020