Stock standard gti is 11 to 12 psi, and remapped should build 16 to 19psi depending on its present condition. Well kept and absolutely nothing off spec will give more of course etc. and if it builds the lower boost levels it may need some looking at where the maf sensor, carbon build-up on the intake vlaves, plugs, coils, fuel filter, etc. So if you are able to run some vcds data logs you should have no problem sorting out any issues with it.
