PCM1704 in a Parasound D/AC 1500

[Salar]

Hi,
I have a DF1704 and PCM1704 and could implement them in the D/A board of my Parasound DAC-1500. The original D/A converters are PCM63.
The Parasound has two complete stereo D/A boards, when using XLR, the second D/A board supplies the negative signal.
I already removed the inverter chip for the second D/A board, now i could mod the parasound with an additional DF1704 and a pair of PCM1704 in the second board.
So to say two independent converters in one cabinet...

But are there any benefits in modding a D/A section originally designed for the PCM63? What about the analog section? I searched but did not find satisfying answers if the design of the analog stage will perfectly fit the PCM1704, or if op-amps have to be replaced as well...
All the best,
Sal