Interesting enough DSP8000, 7000, 6000, 5500, 5000 states about future support of 192kHz.
Only DSP5200, 3100 were left out. Makes me wonder if they are "hardware" inferior to other siblings.. This is a bit out of topic.
172/192kHz over SPDIF is not official standard, but SPDIF COAXIAL DO support this. TacT's processor can do 192kHz over coaxial (but not optical SPDIF, optical is limited to 96kHz)
My 5200 does not accept 172kHz signal as well. The screen will just keep on flashing.
Since 8000 states it will support 192kHz in future software, though the web page haven't been updated for a long time, just wonder if anyone have successful experience with 192kHz signal. It might be the speaker can support 192kHz, but not 172kHz

? Unfortunately I don't have 192kHz DVD-A...
I believe there are quite a few users on this forum also have modded player from DVDUpgrades

This board also output SACD at 88/172kHz.
Hearing SACD though 88kHz is already a wonderful experience and I just cannot imaging when it's working at 172kHz...