Actually, Turbos and Super Chargers have been around for a long time in aviation even before the Merlins. Today most aviation turbo charging is called Turbo Normalizing which never exceds the sea level manifold presure. So it is never "boosted" except when compaired to the ambient presure outside and always less then 1 bar.

Well I can see the logic behind the pre-turbo exhaust being under enough back pressure, since the turbo is an obstruction to the flow. So that raises the question is the egr inlet pipe before or after the turbo? I would imagine before, in order to match the intake pressure and prevent it from bleeding off addition boost. So that would mean the exhaust side is under more presure to allow it to over come the intakes boost.

Before we can say it won't work The question still needs to be answered " Under what manifold pressure is the EGR valve opened ?"

And do we know if the MAP sensor(s) monitor a drop in pressure and automatically correct the drop by closing the EGR?

We may be on to something else. Since the system seems the be rather sophisticated it may just choose to keep the EGR closed each time it begins to open it. The most sophisticated systems are sometimes the easiest to fool.

What information does the ECU use to open and close the valve? The wires on the EGR valve only tell the ecu if the valve is full open or closed.