YES. It sure does. With my aftermarket BOV, on seperate pipe, and I have the stocker blocked off with a plate, it makes boost hit harder!
If sometimes changing gears just as you hit boost, it is quite a big thud of the disengaging of my clutch (it's a ceramic one) and I can notice that the car just hit boost "right then" when I changed.
If that makes any sense
I for one, will be keeping my BOV mod for when I go to the drags