With using a smaller driver like the 4" there a certain physics that you can't overcome though. One thing to note as well as providing a linear response, excellent on and off-axis performance with special emphasis on the speech discrimination band (which as human beings we are most critical to). You also want to include in the design as close to the power handling and bottom end extension of the M60 as well.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne