Lugano,
It might have been better if you had waited a little before you pulled the trigger. I must echo Rich's comment.
You wrote that you want to upgrade to improve the sound. I am not sure you are going to get much of that. The older Harmans used to be more than just decent. What you will get are lots of features, some good, many rarely useful. You will also get what I consider a very nice looking component, simple and elegant, and looking better than the modest price would suggest, and good build quality. Tastes differ but I would take a Yammy over a Denon or Sony any day.
I have my doubts where the sound quality is concerned. I have a Yammy 1600. I doubt that the pre and power amps in the 1600, 2600, 1700, 2700 are very different. Since you are going to use it to drive your B&Ws instead of your CLSs the power amp part should be fine.
However, replacing the pre-amp part of the Yammy 1600 improved the (stereo) sound quality much more than replacing the power amp part. Why would the pre-amps in the 2700 be better. IMO, Yamaha focused on adding features instead of improving the sound. For your sake I hope that I am wrong re. the 2700.
Understand me right, I like my Yammy because it looks and feels so well and because it sounds OK in my non-challenging poor man's "home theatre" setup (nothing more than a Polk Sound Bar plus Dynamo sub, good grief). It is reliable and easy to use, and has a good remote control unit, too.
It sounds well enough for my current low end needs. However, if I were to upgrade to something better sounding I would forget the sub-2k Denons and Pioneers and Sonys, and research Emotiva and Outlaw Audio components instead, and probably end up with an Arcam 350 or better... (In my limited expereince Arcam stuff may not be as reliable, but when it works it sounds really, really nice. If it does not work Arcam will fix or replace it.)