Just like almost everyone else, my Boxster had been shedding bits of black foam off the HVAC blend doors and blowing them at us every time we used the heater or AC and I finally got around to addressing the issue. I chose to access the blend doors through the heater core housing following tutorials found on Rennlist. The first (
https://rennlist.com/forums/996-forum/1183277-repairing-the-black-foam-coming-out-of-vent-issue.html) shows how to access and remove the outer blend door and the other (
https://rennlist.com/forums/996-forum/1280005-repairing-the-inner-vent-door-black-foam-issue.html) shows how to recover the inner door. This isn't a quick and easy project but is one that a patient and careful shade tree mechanic (with hands that aren't too over-sized) should be able to accomplish.
A couple of things that I did differently than the tutorial;
Before disconnecting the hoses from the heater core I loosened the coolant fill cap in the rear trunk. With no pressure in the system I only lost a small dribble of coolant without clamping the hoses. Wine corks are just the right size to plug the disconnected hoses. No crushed hoses, no bulky clamps in the way.
The material I used to cover the doors was craft store self-adhesive EVA foam. The stuff is available in 12"x12" sheets that's about the same thickness as the original foam. Easy to cut down to the proper size, no need to use a bunch of narrow strips of tape. Take a look -
More photos here;
https://rx19jones.wixsite.com/projectboxster/projectboxster7
Cheers! - dj