I've researched and read as much as I can find regarding this noise (Turbo sounds like supercharger, turbo whine, turbo siren, etc.). I found a video on another forum where a it mad a similar noise but was at a much lower RPM and had no load / was in neutral. That case ended up being a leaking WG.
I also just saw another similar issue with a chargepipe on the STi forums. This is interesting because my ER charge pipe does not fit perfectly flush against the throttle body. It is on good enough for the uclap to hold it on but the left side (or towards the front of the car) of the Charepipe is off the throttle body by maybe 1-2mm. It's been like this since day one (was my first mod) and again never made this noise when I was running Cobb.
Boosted and I plan to diagnoise a bit more this weekend. What i'd like to know are any idea's, tricks or ways we can further troubleshoot to identify rootcause. If it is truly the turbo going out then so be it but my intuition tells me that there something else that is either leaking or causing the turbo to work hard to meet target than it actually needs to... Just posting up a few updates on what i've found in research.