First, is your BOV the oldschool Blitz SS, or the newer, SS-DD? I have the old SS and love it. I don't give 2-shits about whatever 'SRT cool' is... I've had this BOV since my old 180SX and intend to keep it till it's no longer of use. I like the whoosh & the slight flutter sound that follows.
If you bought it new, then you may disregard this (or not)... The BOV is extremely simple, and sometimes, stuff gets between the piston & wall where the seal is. Without needing to replace the spring, you can dissasemble the BOV & give everything a good clean & lube to ensure nothing is causing it to hang up... I've had my BOV stick closed before- causing what you are describing.
No need to get the upgraded spring- this is for higher boost applications and will only make it not open as easily... and due to the larger/longer spring, the piston does not travel as far (opens less)... If you're only running .7 - 1.2bar, the OEM spring is your best bet.
^^As you see, the upgraded spring is pretty monstrous! Needless to say, I run the upgraded spring (boosting 25+psi) and the BOV opens just fine at 1.0bar, as well as 1.6... The majority of the sound is the whoosh... but toward the end of the cycle, there will nearly always be a little bit of ch-ch-ch as the vast amount of pressure has bled off to atmosphere; but there is still the remnants in the system that were not of significant pressure to open the valve- This is normal; and the only way to avoid this is to recirculate.
Either your BOV needs to be adjusted 'looser', or it may be hanging closed due to debris in the chamber. A little bit of flutter is nothing to worry about- A lot of it is.
This 'flutter' is not compressor surge; it's just flutter as the pressure in the charge piping stabilizes. Compressor surge happens for reasons other than a BOV.