Instrument cluster squeak
 

Put your hand on the instrument cluster hood of your 986 and move it front to back a little. Does it make a plastic-on-plastic squeak?

Mine did before I added felt to every place plastic touches plastic between the dash and instrument cluster. The process is to remove the cluster, cut adhesive backed felt strips to fit near each clip and near the locations where the screws attach the cluster to the dash. And then a few thin strips around the perimeter of the hood to prevent it from contacting the dash. Now no more squeak.

Now press on the windshield vents and the remote detector at the base of the windshield, any squeaking there? More felt.

Porsche went cheap with materials in these cars big time. They could have easily chosen a plastic that can touch another piece of plastic without squeaking.