He's talking about the difficulty of passing an engineers inspection with a manic hub adapter. You started the thread to talk about the adapter, right?
I've had one crappy kit sprocket not seat the chain properly too, had to get out the dremel and "fix" it. It had really bad vibes, and felt like gravel in the wheel bearing. That'd be something to watch for too, for future readers.
Happy cruising on your less-vibey ride