HKS is a good valve but for low boost you want a dual chamber BOV really the HKS is one of these so that is good but a twin chamber or a pull release valve would work best I believe. Such as teh Blitz Dual Drive, HKS SSQV, Apex'i Twin Chamber(yeah i know its gay), or a Greddy type S.......piston type BOV's like the older Blitz, turboXS and some others are likely to leak and require a lot of pressure to open them usually. The Type S I had which is the LOWEST spring setting on any TurboXS valve didn't open fully till around 6-7 psi.....what you may think is a BOV sound may actually be compressor surge if you don't have a good knowledge of the difference of the sound between them.