In need high-efficency speakers

I recently purchased a preowned Mystere IA-11 40 watt tube integrated amp to replace a 120 wpc SS amp. Overall it has a very satisfying sound with plenty of detail, dynamics and a tight bass for a tube amp.

The problem is the combination of our large town-home living/dining room combo with my 87db DIY Seas Froy Mk3 speaker, powered by the 40 watt amp means it can’t play loud, especially a problem with movies or TV specials.

I was hoping to change to the Zu Audio Omen Mk2 or Klipsch Heresy III high-efficency speakers. My wife and I agree it is unwise to spend that kind of money with our current finances. The Zu Dirty Weekend would be a cheaper option, but the Klipsch would look better in our living room.

So I’m looking for solid advice on what to do from this audiophile community.

Here is a link to my ’Virtual System’ if that will help.

Thanks all,
Another single-driver possibility:

Caintuck Audio - Open Baffle Betsy. Very affordable.

They do need to be out in the room... well away from sides and wall behind to get the best sound. Not certain you can accommodate them in that regard though your overall room dimension is well-suited to them.

See also the Caintuck video at
Markr1 is audio buddy of mine, He used to have the Zu essence , they sound very good, He discovered Omega and He bought the Alnico model speakers, When I listen to this Alnico for two weeks, I can’t listen to my system , they are so musically transparent, with live like capability, Now He traded the his old Alnico single driver, to get the High Output Alnico, this are really very very good speakers...they schooled me though...He sold his Zu speakers as well...
If I remember correctly, the Klipsch Heresy IIIs and its Klipsch cousins in that price range are a bit light on the low end. Only go down to 50-55 hz or so.

Keep the Mystere’, IMO, that should be the anchor of your system, as you are.

I have had a pair of Zu Omen bookshelves for 2 years, and have run them with a pair of DIY Tube mono blocks that I built. They are a good design, but nothing groundbreaking, 40 watts, but the Zu’s sing like a bird with them.

I have NEVER heard anyone say that Zu’s are thin and veiled. Thats just silly sh*t. Check your amp, source, and cables, yo. You are bottlenecking your system somewhere in the chain before the signal gets to your Zu’s.

OP: the Zu’s are "designed around the human voice" and made for "live sound". Read their website? This just means that the SQ has a natural and real presentation.  Zu’s of course are crossover-less designs, so they are fast, nimble with excellent dynamics. But the midrange is gorgeous b/c of the "designs around the human voice" especially with the tubes. 

IMO, Zu’s were made for tubes, you will get an organic sound with very good soundstage. I also own a PrimaLuna HP Integrated, and of course PrimaLuna and Mystere are made by the same company, so I understand the sound you have. 

I would recommend the Dirty Weekends, they are one of the best deals in speaker audio. Run them with the Mystere, and I think you will have a smile on your face. :) 

Lastly, I recommend calling Kevin at Upscale Audio (he is part owner of PrimaLuna and Mystere, ya know?) and asking him to recommend an efficient speaker for your Mystere (which of course he also sells). 
Zu is special  hate  and love product. Some say too harsh and thin,
Some is best product ever been made. 
I belong to first group 
Anyone buying Heresy IIIs should look around for a REL sub, as I've found these to match really well with these (and other) speakers, and in the last few years found a couple of great used RELs for a couple hundred bucks each.