One major difference is that the boost does not directly affect the fuel. There is no boost feedback to the pump at all. Boost is solely controlled by the fuel and wastegate and fuel is only controlled by the throttle. So, if I understand the vw pump correctly, it would be like not having a boost pin at all....the pump has the capability to push as much fuel as made possible by rpm's, at any time. It doesn't have to wait for boost to moderate fuel flow. That's basically what's happening by playing with the taper on the boost pin and the star wheel...it's allowing max fuel to come on with less boost...which in fact, should give you more boost quicker...but that's just a guess.I suspect the boost feedback is primarily an emissions thing.