iFi Nano Black Label upgrade

I'm streaming Spotify Premium through this DAC and my Cyrus One (2 years old), but am looking for a richer, warmer sound. The iFi is more articulate, but it's a little too spare. 

My local hifi shop recommended the Project Pre Box S2 as the closest price point upgrade, and I notice a slight difference but not enough to spend the extra CAD250-300 for it than what I paid for the iFi. If I'm going to upgrade, I'd rather spend $200-400 more for a clearly noticeable upgrade. 

Any recommendations for less than $1k - $1.5k??

For the price point of less than $1k - $1.5k the very best values IMO are found in direct Chinese imports.  But you need to do some research.. 
I have the ifi Nano LE but have it matched with tubes and Vandersteen speakers and it doesn't present as spare. What I would suggest is an NOS dac like the Metrum Acoustic Octave II. These days they think every dac has to have detail above musicality. With the Cyrus One you can put some meat on the bones with an NOS dac.
Unless getting like a tube DAC, most every single high end DAC is aiming for articulate, why pay more money for a less accurate conversion? If you think your DAC is good, and are tech savvy, I would recommend upgrading to something like a MiniDSP SHD, where the DAC is mostly audibly transparent, but has powerful DSP capabilities to add that warmth. Or, get an old school analog EQ to add after your current DAC.