I am happy to answer any questions as I have come here to get my headphone questions answered.
I have owned every speaker that you can imagine including ribbons, stats, radials, etc, the Grande EM flattens them all. I have also owned 3 other pairs of Focal Utopias and the EM flattens all of those to. So much so that it is almost hard to believe that the Grande, and the Grande EM are built by the same company.
The adjustable "focus array" and crossover come in very handy with setup options an is not fluff.
The MDF cabinet is the way to go and Wilson Alexandria X2 S2 (noted for having the best bass and dynamics around), doesn't come close.
They are efficient at 94db but I am feeding them 800WPC and I have used it as these are current hungry and will effortlessly break the sound barrier so it is tempting to do so on occasion.
They like a big room. I am in a 38 X 24 X 21 which allows the bass to open up and they really do reach to 16Hz and shake the foundation.
Also, the EM woofer is amazing. You can click the bass level up or down a notch to compensate for issues in the recording. As you are changing only the magnetic field on a driver that operates from 50Hz down, there is NO change in integration when doing this. It is amazing and nothing like changing the level on a sub.
The $180K is steep, as is the other $250K for the rest of the rig but they will trump anything that I have hear. Including the mighty MBL 101X at $250K.