Cracking Sound from Boxster Top?

[mcrg00]

Thanks to everyone for your input. Pedro's center bow comment makes the most sense to me because the sound doesn't occur when the top is down. And it sounds like it's coming from just above my left ear.

The trick question now for me is where to spray the silicone. I see that there is a small panel above the driver's side window that flips up, but don't know if that's the place to spray or not. Would appreciate recommendations.

Thanks again...mcrg00