After a year at 18psi, and a few weeks at 23psi, I finally put a BEEEEE OOOOOOO VEEEEEEE on the Mustang.

I put a used HKS SSQV on. I like the sound, but I like the sound of compressor surge better even though it wasn't very good for the turbo . The BOV is actually louder because of the higher pitch. You can still hear the compressor surge a bit at light throttle, but under full throttle, all you hear is the HKS.