A couple points:
'Dead-heading' a pump and getting a high pressure does not necessarily mean it's good enough. That's just the max pressure it can make at 0 flow. All pumps deliver less volume as the pressure rises. The best test for the fuel pump is to put it under the highest pressure AND highest flow situation it's going to see, and check the pressure. Unfortunately if you dont have a pressure gauge with a long hose, you either have to extend the hose or take the hood off to be able to see the pressure while driving high rpm and max boost.
A TBI pump will only make ~50 psi max, in my experience. Not even enough to safely run a stock turbo setup.
But, there's no way the fuel pump is your problem here anyway.