Best DAC for CD redbook playback from a PS Audio Perfectwave transport

I just purchased a PS Audio PWT and will use it to listen to redbook CDs. I've read that the best playback is with an I2S hdmi cable. So, a suitable dac would be one with an I2S input, such as either a Wyred4Sound dac or a PS Audio PWD. But, if it's just for redbook CD playback, can I suffice with an older MK1 version or do the updated versions (which I presume are primarily geared toward improving computer based systems) also significantly improve CD SQ? Again, it's just for CD playback.