i drove around with my BBV closed all of the time, for who knows how long. Since the car was tuned for the valve being closed, I had no KR issues. Naturally if you adjust the valve and don't add extra fuel there would be KR.
As far as the valve not being adjusted right from the factory, seems odd. IIRC the tool used to set the BBV is a fixed position tool. There is no adjustment. Looks like it works like a jig. Put it on and tighten up the nuts, and then remove. Time to go pull out the and look at the procedure again.
Just looked up the install process and it would be real difficult to get it wrong, but anything is possible.
I'm certainly with everyone else on not messing with the BBV. All of that boost even with the right fuel made taking off from a light without spinning the tires really difficult. Basically a waste to have that much boost at the bottom on an engine with so much torque.
