Here's a resurrection of an ancient post for you <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />
I've noticed that one of the rattles I attributed to my cab top is actually the seat back of the passenger seat rattling back and forth when the car hits a "road feature" on one side, or similar to hitting a speed bump at an angle. The car naturally "racks", or flexes from one front corner to the rear opposing corner, and the passenger-side seat back is tossed back and forth and makes a very loud series of clunks or rattles, which originate in the seat's hinge and pins if I'm not mistaken. I remember this occurring in my 944S, too.
Is there a fix besides installing a permanent passenger?
TT