I am curious about this too, my pockets are not deep enough to be in the game so I don't know if procharger makes custom impellers to create a compressor map different from any of the stock ones. If not I do not understand how you would efficiently get 52+ pounds of boost from a compressor designed for a max of 40.
As far as the flow goes the combination of the biggest f-2s creates 37.5% more flow than the biggest single f-3 so on a big inch motor like a 632 you would really have something.
Of course my dream engine has always a 5.080 by 4.5 inch 730 semi hemi (or prefferably, with the wedge heads they had talked about due to the reduced wieght) with twin f3s this would allow you to have a great rod/piston/ring package and an engine that would rev with a wide power band, good efficiency and relatively low maintainence.
Maybe His Highness Sheikh Khalid Bin Hamid Al Thani will read this and help me out