What is this stuff?
 

This stuff has been coming out all of my air conditioning vents.
Does this occur with anybody else as well? I live in florida so the car has been out in the heat and sun, maybe that has something to do with it.
Seems like some type of insulation being spit out, I'm hoping it's nothing serious..

HVAC door falling apart. After a while you won't be able to get just hot or cold air but a blend of both.

Heating Ventilation Air Conditioning

And yes one of my boxsters is starting to do this too. :(

Mine as well!

This should have a name, like Porsnot or phlegmsche.

I get hot and cold separately, but it will com out of all three sections rather than just the selected ones (top, middle, feet).

What a pain in the ass. This car is gonna drive me out of my mind. I've got this issue as well!

Interesting...never seen that before. Is it some sort of foam? And will it be an easy replacement, this HVAC door?

The stuff is foam from your air ducts. The foam falls apart when it gets old and breaks apart . You receive it when you turn the fan on. It will come out of every vent. It will stain your seat and clothes. Turn you fan on high and quickly open and close your vents manually to get the foam moving out towards you and the vent. Pick the foam out with what ever you have. I have gotten alot out but once in a while a piece will still fly out. This happened in my Audi and MB. It's a German thing.

It reminds me of when the foam in the pistol cases or in the helmets get really old (read: older than 10 years old) and the stuff just crumbles when you touch it.