My speakers don't "dissapear"

Nordost will give you detail but not not alot of warmth or bone to the music IMHO.

Based on your last post you need acoustic treatment bigtime - if you can't aesthetically treat a highly reflective space then don't throw good money after bad with expensive cables, IMHO. You simply won't be able to re-create that great sound in the dealership. Look on the bright side... you live in Greece and while you are still enjoying the sun I'll be shoveling snow and freezing my %^$&'s off!!

I second Soix's response.before you buy new cables or treatment,try to borrow a pair of speakers and see if the problem persists

Nordost cables works well with Krell IMHO, contrary to what other folks said. With your system you must have the support of the dealer, he should be able to let your speakers disappear. Of course, the acoustic of the room is very important and also here, a good dealer should be able to give you some good suggestion, and I do not mean "spend more money"!!!
Good luck!

40 hours on a new pair of high end speakers? This is not the time to make judgements about what your system will or will not do, period. All this conjecture means very little in my opinion. All your gear and cables need to continue to settle in, and the speakers need break in, or whatever you choose to call it. Leave the system untouched other than to play music, and if you can 24/7. From all reports, these speakers need hundreds of hours. Leave all your cables untouched.