Like many of you, I've been doing this for a ling time, and if there is anything I know, it is that I cannot tell conclusively what any single component is doing in a foreign system/room. Even changing the component for another (e.g. Amp A vs Amp B) simply tells you that the differences are due to interaction. As an Ayre dealer, I've heard their demos at CES sound awful, TO ME, yet I've also heard virtually the same sound magnificent. Rooms, placement, music selection, AND my mood at the time, play huge roles in the perception. If you really want to know what the component sounds like, in your room, then the only way to know is to borrow/buy it and use it for some extended period. Play the system with different music, at different times to ensure your mood is not a factor.
I once had a client who fought bad traffic to meet me, and when he finally arrived, he was in a bad mood, with a pounding headache. I suggested we go for dinner, relax and just talk. We listened a little, talked about his needs, and we made an appointment for us to bring some stuff to his house. The same system sounded much better to him in his home (though I thought our set up at the store sounded much better, same system).
My 2 cents only, but hopefully worthy of thought.