Preamp or Processor First

I have been slowly building my home theater and 2 channel system.  I have Sonus Faber Guaneri Tradition with the Vox center channel.  I am currently using D’Agostino Classic 3 amp and a Yamaha CX-A5100 processor.  Streaming with a Bluesound Node 2 and Transparent Cables and interconnects.  It sounds pretty good considering my front end.

I am ready for my next upgrade and I am thinking of replacing my Yamaha with the Mcintosh MX170.  While I use the system for movies and TV, I really want to improve the sound for 2 channel listening.  My question is this, should i get the MX170 or get a stereo preamp first.  Will the MX170 sound nearly as good as a say an Audio Research REF6?  If the MX170 would be a massive increase over the Yamaha and sound great with music but also improve movies I would probably go that route.  But if an excellent tube preamp can really make an even bigger improvement for music then I might wait on the processor.  

Just to share my plan; I will eventually have both, along with a much better streamer/DAC and will move the Guarneri’s to the study and replace them with the Amati’s for the mains.  I will ultimately use the Classic 3 for center and rear and get monoblocks for the Amati’s.

Any feedback would be appreciated.

~Mobius