Sonus Faber Amati Tradition or Serafino G2

That's a really large space and if your listening taste includes having a robust bass foundation both of those speakers will be challenged.  The previous gen Amati were known to be beautiful sounding speakers but bass shy.  I spent some time with the Amati's in a large space like yours and the Mac MA12000 driving them was having a hard time.  I'm pretty sue at some point it was clipping.  Moving on to the new gen SF, they addressed the bass and the Amati and Sarafino's have more bass presence.  Between the old gen Amati and current gen Sara's they should be very similar.

If I were you I would consider looking for a used Il Cremonese.   For whatever reason the Il Cremonese are not holding their value all that well and they are steeply discounted on the second hand market.  I would take a hard look at that option.  Good luck and cheers.

Thank you so much for your response. You make valid point. I will look into Cremonese as well. However, I suspect they might be too big in our room from an esthetic perspective (this is a family room that our family uses to hangout and entertainment space). I typically do not listen to music more than 75db avg. spl.  Based on your experience, do you think MA12000 would drive these speakers well at moderate volumes?

You have an excellent integrated in you rack and I would suggest only changing one variable in your system at a time.  Settle on your new speakers and see how they play with your Accuphase. Then, if your not satisfied, audition different eclectonics.  I wasn't recommending the MA12000, just communicating my experience that the Amati's were lacking bass and at reference levels perhaps the electronics were holding them back.  Keep in mind that the SF speakers are already warm sounding and putting a tube pre-amp stage in front of them will only make them even warmer.  

Thanks again for your guidance here. Make a lot of sense. Also, would like to hear from other of their experiences with these two speakers. I am just trying to gather as much information as possible at this time.