Does it have a digital output (coax or toslink)? If so, yes you can use a DAC for much better sound. The other advantage of an external DAC is that you can play around with different ones to get the sound you like.
Also, if the Pioneer breaks, which changers often do, you aren't stuck with a unit with expensive mods.
Also, if the Pioneer breaks, which changers often do, you aren't stuck with a unit with expensive mods.