I'll save you the hassle -- it's basic physics.i have heard about this. Would be interested to see some real world data if available? I haven't been able to find anything.
The "sound" you hear is the compressor wheel stalling on throttle-off as the rotational momentum of the wheel tries to compress intake charge against a closed throttle plate. Normally the wheel's rotational momentum would bleed away over time. Without a BPV, the compressed charge has nowhere to go except back to the compressor wheel (an acoustic pressure spike) that stalls the wheel. When the throttle plate is opened, the compressor now needs to spin up in order to provide useable boost.
I am constantly amazed the number of people who destroy proper engineering in order to peacock to their peers. It makes me physically sick. It's no wonder I despise millennial car "enthusiasts."