I don't have much to add other than I bought a kamak p18 exhaust housing and it's almost identical to the factory turbo. It is evident that there is less attention to detail in the machining in some areas though.
It's hard to know what to make of it. If they can't pay attention to detail with something as simple as a cast exhaust housing, I'm not sure I would trust their complete turbos. then again the exhaust housing isn't necessarily a precision part in many ways, so it's possible that they just cut out "unnecessary" work.