Dropped the Rex at the Dealer this morning to investigate my boost leak/belt squeal sound.
They ran the fog test on her respiratory system and found no leaks. A good sign. They couldn't, however, duplicate the noise. I had to go there, drive the car on 95 with a tech in the car to show him. Luckily it made the noise (it sometimes doesn't), and I also played the above vid on my sound system for the whole shop.
Still a mystery, but he thinks it might be the A/C belt, being that it's a fixed belt with no adjustment... so if it should stretch a bit, it's done. They're replacing now, so we'll see by end of day.