not really a turbo based question, but maybe more of a problem getting the exhaust to the turbo?
pull the MAF pipe off to the turbo and see if the turbo is still tight-
if so, then check for excessive exhaust leaks or a bound up wastegate puck- if the car spools up slow and runs low boost, maybe the wastegate is not seated properly hence the low boost-
pressure is required to the wastegate to lower boost, so if the hoses are bad, you will get more boost-
also- taking a hose from the silver compressor housing to the wastegate will get you 12 psi and no creep-
check the above and see what you get-
BW