2014 GC F06 WOT Noise

[PARANOlD]

Wanted to throw this out and see if it's normal, since I am more familiar with the N54 platform and its turbo sounds:

Bought a GC with about 70k miles a while back and have been making subtle cosmetic and mechanical changes preparing for a tune. First thing was plugs and Dinan coils, and next I installed the Burger Tuning intakes and charge pipes.

I didn't notice this before installing the intakes and charge pipes, but under WOT I notice a sound that I wouldn't necessarily call rattle, more of a high pitch fluctuation sound. I'm wondering if the turbos just sound like this, or if it's more likely to be waste gates or even some kind of leak at one of the silicone joints.

Would be difficult to get a sound sample so that's the best I can describe it. Any info appreciated - no issues with performance other than the usual turbo spool time and the car still rips.