Odd squeak when on boost

[BSOD2600]

During my 450 mi trip home from college this weekend, I had two issues. One was around Willamette pass area (5100 ft) I started to get some bad pinging when on boost. The weather was ~80-90F out too. When I put in some fuel injector cleaner (had some in the trunk), it helped some. But after being on boost for a few seconds, the pinging would come back. Finally was able to get some octane booster and that fixed the problem. So I guess the last fill-up the gas was messed up or something, since I swear I saw the kid put in 92.

Several hours later on I-5, I noticed then when I would get on boost, there was some sort of sqeaking coming from the front right area of the engine bay. Once home, I drove around the block and recorded 2 clips of what it sounds like.

The sound clip.

First clip is simply driving along and flooring it. Noise is very easy to hear.
Second clip is from a dead stop, flooring it through the gears. Noise is harder to hear.

Any ideas WTF the sound is? Nothing appears obviously loose in the engine bay, but I could've missed something. The fact the sound ONLY happens when I'm on boost, makes me think its something related to the turbo? Still stock turbo/boost.

[555BCTurbo]

I didn't listen to the video...but a squeak under boost is probably a small boost leak that is whistling...

Also...if it pings, get out of throttle...ping=dead motor

[BSOD2600]

It really doesn't sound like a leak / air though. More like metal squeaking. Drove it cold tonight and didn't hear any 'squeaking' until the car had warmed up some.
Also noticed the boost gauge only was reading ~6-7psi, where as it typically reads ~8 psi. Although, I did just change elevations (back in Seattle now), so haven't gotten use to the car's behavior here yet.

[Aerotech]

All of your spark plugs tight?

Lots of detonation creates really nasty shock pressures in the cylinder, keep an eye on your coolant level and oil condition for the next few days, you may have damaged a head gasket... my old motor made a clattering chirp noise only on boost, turned out to be a bad head gasket

[BSOD2600]

Funny you should mention the coolant -- I did notice the coolant overflow tank is lower than it normally is. Typically I have it close to the top of the bottle, but now the level is at least half empty. The whole 450mi drive, the temps never were hot at all nor any CEL.

Took the car by Smart Service this evening and had a tech drive it. After putting it up on the rack, he thinks its a combo of my front heat shield. Also where the cat connects to the down-pipe makes a very similar noise (when whacked with a rubber mallet); he thinks it might have separated. Going to go get those two welded up somewhere this week and *hopefully* that fixes my noise.

[BSOD2600]

Got two heat shields tack welded. The squeak noise has decreased substantially, but occasionally is still present. Guess I was barking up the wrong tree with the engine/turbo issues...

[Bdub]

Mine was/is making the same noise.
It appears that a bolt which holds the turbo cooling chimney has been sheared off where it mounts to the engine.
Under a decent amount of boost it rattles around like a sonofabitch. I can't seem to get the damn thing tight enough to stop rattling around. I've tried just about everything from adding some lock washers to different bolts. It doesn't help that the chimney had to be cut back to make room for the 3" DP.