Very old thread I know, but still valid.
I got my 996TT 2003 windshield replaced couple of weeks ago by an OPC so I'm pretty confident they used the latest seal. However this rattle, that I thought was coming from the dash appeared right after the change. Of course the OPC's view was that it had nothing to do with the windshield change, but they could open up the dash on my expense if I wanted.
The fact that the rattle went away for few minutes after every wash was the key to find this thread. I ordered the cord from FVD, applied two-fold wherever it would fit and now after a week of d