I just installed my Hallman mbc on my gst. All stock I was at 15psi. Installed the ,bc like this Best way to install a MBC - DSM Forums And there is no change at all.... Also, another reason I wanted to install it was to get rid of the boost fluctuate in higher gears. ie 15-12-15-12 it will do this till you let go of the throttle. Will a mbc help this?