[FRporsche]

It's called silicone and never using your sunroof again.

I guess you could use silicone before the winter, then break the seal and use the sunroof in the summer, and just put new silicone every time. This borders on ghetto but hey I understand sometimes you just gotta cut some corners.

But clean unclogged sunroof drains will help the situation. You can have a bad seal and still keep the interior mostly dry if the drain tubes are unclogged.