BBV wouldnt make a difference either way. just because air loops around the blower doesnt mean any more or less air is coming into the system. You just need to measure net draw into the motor as effectively as possible which isnt hard at all. You'll never need a blow off as there is no air pushing against a throttle blade.. The only reason people use blowoffs is to not bend throttle blades and prevent turbo compressor surge... you have no risk of either.
I noticed you have another thread regarding this.. and if you are worried about the driveby internet naysayers saying its impossible to tune these.. i would probably wait and see myself. From experience I would say that a maf sensor responds the best when it is placed as close as possible to the intake valves... Without that you will want to introduce what we would call an "interp" or "AE" factor on the throttle position which will compensate for the now "measurable" pressure lag you would have with a massive intake plenumn.
