Well I guess what my concern is the MBC does not hold vacuum...sort of a free flow but restricts for control of boost. With the MBC tapped on the BOV line it did not seem to open the BOV very well between shifts causing the turbo to stumble.
I hooked it up to the Red dashed line on the Throttle body and without setting the MBC any different it went to 20 PSI!
I cranked down the MBC for my 15 PSI (6000' altitude allows for more boost pressure without incedent) and now I can hear the BOV working much better with less lag between shifts.
I guess another concern of mine for the MBC to the Red dashed line was...what does that go to and would not having much vacuum to it hurt anything?