Hi - Perhaps an obvious question: Are the 103's USB ports able to take advantage of the Vanity HD DoP, whether via PCM or via DSD to a PS Audio Directstream dac via spdif cable? Thanks,

Hi highstream,
There is no relationship between 103's USB ports and the VanityHD board. Of course you can use USB storage (flash drive) attached to 103's USB ports to play back audio into the PS Audio DS via VanityHD, but that is about it.
Regards,
Pavel