I initially posted the thread s2000junky alluded to earlier.

As spdracerut mentions, the restrictor method is restricting your CFM, not boost, so max boost would not be at redline. I calculated 7500 RPM for a 510 CFM restrictor (2.12 inch) for the theorized pulley size (13 psi, probably 3") and engine (AP2) in my thread.

I never did this, but it does have several advantages over a bleed system such as a passive failsafe that would never allow an overboost like the bleed system and the fact that I believe it would be more efficient (creates vacuum at inlet of compressor due to restrictor, making the blower work less for a given compression ratio to arrive at a target boost level, rather than compressing more air than would be used and bleed off the excess).

But all that said, I think most people just decide they want more boost and make the mods necessary to allow their car to use the pulley to the maximum potential. Hence no one has really gone through with this.