Harbeth vs Vandersteen vs Sonner

I am a Vandy fan, as most here know.
I haven't heard of Sonner, but their website looks impressive and speakers appear to be well constructed.
My concern with Sonner is the 3.8 minimum impedance they list for the speaker. That is pretty low, so I would think you would need an amp with some 'muscle' to allow them to perform at their best.
It looks like Adirondack Audio in Brooklyn sells them.
I might just call for an audition.
Bob

Treo's aren't power demanding. I would say any decent 75-100 wpc amp should power them sufficiently- unless you want to have a block party.
I use an Atmasphere MA-1 for my winter listening with the Treo's.

And, if you end up getting the Vandy subs, then you'll really be good to go.
B

@OP,
Johnny (audioconnection) is a Vandy dealer as well as a stand up guy here on Audiogon. He knows just about everything audio- and, I don't make that statement lightly.
If you want good advice, PM him. 
And, he won't try to sell you something.
I never cared for dealers until I met him.
Bob

@OP,
Great to hear your new system is up and running and that you love it!
Vandy,  Aesthetix, and AQ make a great system.

Now....how can I improve it?

Well, getting a Sub 3 or two would be my recommendation. Johnny and Samir installed my pair and I have to say I think I have something close to a Quatro. (I'd buy the Quatro's but my space is limited).
BTW, Vandersteen has a new forum on the website. It would be nice to see you there.
Bob

@tomic601 ,
Great point.
I put my preamp and subs on Townshend platforms and bars.
IMHO, it 'tightened' up the sound, especially the bass.-Just a clearer/cleaner sound.
I want to add some Pods to my monoblocks, but they are so dang heavy...

And, to throw fat to the fire.
The new AQ power cords are really something. John Rutan recommends starting with Source and working your way down.

Bob