looking for a more efficient speaker.....

I think you’re making up an amp problem where there is none.  The McCormack DNA-500 is a beast, and your amp almost doubles power to 900Wpc into 4 Ohms.  You’ve gotta be kidding me if you think that’s not enough power.  Look elsewhere for whatever issue you think you have.  This is absolutely silly. 

soix  also i talked with dr lee at acoustic zenn, ask if there could be a problem with the wow II's since i got rid of the tara labs for the same reason.  he told me not to tighten the interconnects to tight this will alter the headroom and clarity and he was right, just fyi.......

That’s very interesting, especially as I too have AZ interconnects/cables and probably over-tightening myself.  Is this a recent issue or has it been present the whole time you’ve had this setup?  Only other thought I have is swapping tubes in your preamp.  Best of luck, and please keep us posted.