I don't think you can add a PSX-R to a CD6SE...
How about getting Cyrus to upgrade to an 8SE; cheaper option than a DAC-X.
FWIW, I went from standard DAC in my 8XPd to the Qx DAC and noticed a massive difference. The 8SE should approach the Qx DAC in terms of performance, and then you also have the option of a PSX-R.