Wow. After almost twenty years, somebody finally reinvented the Hypermag.
Seriously, though. Fox River Games did almost this exact thing back about the same time SP was doing the "Black Box" mods in the early 90s. The box lowered
the chamber pressure by roughly ten percent, the Hyper raised
chamber pressures by about ten percent.
It did work- as in, the higher pressure gave a slight boost to efficiency, though a fair percentage was lost since the gun couldn't draw the tank down as low before shootdown.
Just keep in mind that the higher chamber pressures also produce more pressure on the sear (stiffer trigger, increased wear) and will require retuning your ULT and L10.