At What Price Point ?

CD player that would show audible improvement over Musical Fidelity M1A dac with Theta Miles as transport... At What Price Point ?

Musical Fidelity M1A dac
Quicksilver Line Stage (non-remote) 2010
Quicksilver 90 watt silver monos
Speakers: 12x14x9 room... Fritz Rev 5 (upgraded drivers) Scanspeak Illuminator 5 inch woofer, Revelator tweeter
WyWires Blue speakers Cables
Kimber KCAG (amp to pre)
Kimber Silver Streak (dac to pre)
DH Labs digital (Theta Miles CD transport to dac)
Kimber PK 10 Gold (pre to API Power Wedge 1)
DH Labs Encore (from dac and CD transport)
amps hard wired

First I haven't heard that DAC but have heard and owned a lot of DAC's over a lot of price points and have a good idea what to expect at certain price points. At the about $700.00 of that DAC I would look at the following DAC's to easily best it starting at about $1.2K (in order of increasing price):

Tranquility DAC
Metrum DAC fed by something like an Audiophellio 2
WFS fed by something like an Audiophellio 2

As an all out option, but at a much higher price, a PDX.

A Playback Designs is the best sound I have ever heard - but only via DSD.

My gut tells me the M51 is probably your best bet.