Very interesting MR. Watson...I, Sherlock thinks it's a noise...........suggestion, have someone turn off the ignition and you listen through the side air vents. If a fan motor is running, it could be the noise of it winding down and going bad. Also, remove cover behind seat to access front engine. Again listen and see if you can hear any noises in this area. FIRST THOUGHT....it also almost sounds like a cd player whirlling down. I had one that a made that kind of noise when you stopped the cd. No, it wasn't in my Boxster.
