bit of a longshot.... but try calling mark frisby at rapidgb
Rapid GB - About Us - he knows loads of stuff about supercharging small block chev's but has also done bmw's etc etc - he may just be able to point you in the right direction?
i'm running a 5psi kit on my holden - 530bhp and actually does more mpg than originally! with 5psi no need for expensive intercoolers - just loads more oomph! - its a vortec centrifugal kit so no clutch frying at take off ;-)