Our car runs OEM vacuum style wastegate control, and makes well into the 900'sWHP, soon to be more. On 100% Stock style wastegates on a set of GC's we did almost 850WHP. The factory N54 wastegate system is better than an EWG system for all intents and purposes as it offers much more precise control. They can rattle if not set up right, but that is the only drawback.Other platforms add external wastegates because the oem gate either can't flow enough or has trouble staying closed at higher hp levels. This is not a problem on N54 - OE style wastegates have done over 700 whp on pures, MMP, etc.
The only explanation here is whoever put this contraption together ate too much glue as a child.