EFI engines can vent BOV air into the atmosphere, CIS engines function optimally when all the air is metered by the flapper valve and circulated past the throttle plate.
I would think that having a BOV just past the turbo and just before the throttle would be a nice safety feature in a high boost EFI application.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8