boost drop???

I notice that everytime i shift gear while flooring my car the boost drops. I am curently running with a mbc set at 14 psi. first gear will hit 14 psi in a breeze and with almost no turbo lag, however as soon as i throw it in second my boost drops to about 5 psi and then i have to wait for the spool up again, which takes forever. I usually end up shifting gear ,because my rpm has already redlined, before i even get to 14 psi. This same thing happens in third gear. what could be the problem? Could it possibly be my mbc??

I have a 93 tsi awd with 2.5 exhaust, 2.5 downpipe. 2.5 test pipe, k&n filter, rewired fuel pump, stock 14b turbo

boost leak ?

Boost leak is always something to check for....
How is the MBC hooked up?
http://www.belitski.com/cars/talonmods/turbo/vfaqhallman.html

Compare it to this link....