Searching for the most "accurate" speaker (below 15K)

Vermeer,

have you considered Wilson Audio?  I know the secondhand market in Portugal is relatively small, But if you can get a pair of Sophia 3, Watt Puppy 8, or even Sasha 1 used, you will get some amazing resolution and detail.  Can your nagra amp go to 4 ohms?

what part of Portugal are you in? Are you dealing with Imacoustica?

At under 15k the pair why not go for the best (IMO) and pop for a pair of Magnepan 20.7 's.  Pretty hard to beat for the money if you have the room.

I think OP has a small room (around 200 square feet). I used to own Maggie’s and loved them.  The space required for Maggies to fully perform might be a deal breaker here. 

Thiel CS 2.4 or CS 2.7- natural, fast, accurate.
Happy Listening!

These days have been hectic and I was not able to come back to discussion before ...

@marktomaras : yes, I know Imacustica (who doesn´t in Portugal? ;)). I must confess that Wilson is not exactly my sound ... and currently they have no opportunities. They have, however a pair of Martin Logan Summit X which are going to be sold with a good discount since that line has been discontinued. I'm not sure however if they will be a good fit for a small room ... And I also don't know how my amplifier will handle them ...

@david_ten : it is a living room in a restored 100 years old building. It is a suspended wood floor, so I've playing with isolation solutions to decouple the speakers from the floor ...

From my perspective I don't feel the discussion has been hijacked by a dealer. Actually there was a very informative post from @audiotroy which I felt was quite honest (btw, it was removed not longer after it was posted). As long as properly identified (and this is the case), I have no problems at all in having dealers taking part of the discussion. We all have biases, not only the dealers ...