Shahinian Obelisk vs VandersteenTreo

Sure, Bob, but calling a dealer in the US won’t help me much here in Russia :-)
The items are not on Audiogon. But I have spoken to the sellers, of course. Thinking...
Looks like Quatro is the way to go, since its bass performance can be tweaked. 

I Didn't know about your being in Russia. That makes things a bit more complicated. I never would have guessed it, as your English is impeccable.
You can certainly PM Johnny R and get great advice for free. He is one of the premier Vandersteen dealers in the US, and for good reason.
I would agree, getting a pair of Quatro's would be the best way to go, for the long run. You have a fairly large room. The Quatro's would be a good fit.
And, Johnny can help you with assessing your current amp and preamp, which, should you get the Quatro's, would probably be worthy of another upgrade in the future.
Bob

Q all the way
11 bands of analog bass EQ
powered sub
your amp works hardly at all
opens up a wide range of tube or SS amps including OTL designs

you could also call Richard....

Gentlemen,
Thanks for the advice.  
Bob, what is Johnny's nickname here on a-gon? Will PM him on the amp choice q.
tomic601,
I am aware that this amp is probably a weak link in my system. A good friend of mine who used to have the Quatro, gave 5 stars to Meridian G57.
Another amp I use is the Sringray II  from Manley. Actually, I am listening to it with Shahinians as I write. Great little amp, but hardly a match for the Quatros.