Anyone looked at the Twisted Pair Audio Opus DAC?

The Twisted Pear Audio modules look interesting.

I am considering using toslink output of the CuBox-i4Pro as a Volumio host device.

I’m outside my expertise, but I think these Twisted Pear modules would accomplish
what I’m looking for:

TOSLINK OPTICAL INPUT MODULE KIT
S/PDIF TRANSCEIVER MODULE
OPUS - A BALANCED DAC
IVY III BALANCED LINESTAGE

Has anyone worked with these or looked into them?

http://www.twistedpearaudio.com/digital/opus.aspx

I have not worked with this DAC but I am also interested in using them in a dual mono setup.

But I would also be interested to know if anybody has worked with their COD dac. I believe the COD would require an output transformer, something like a Lundahl: lundahl.se. Any ideas on which transformer to use would be welcome!