Hello jafant,
Around the same time I had the Vault 2 installed (had to have my dealer run CAT5 cabling to my listening area), I inserted MIT Terminator 2 cables from my LS7 line stage to the Thiel Bass Equalizer and then to the amp. Former cables were Audioquest Golden Gate and King Cobra to the amp.
While I do believe the MIT's are probably more resolving in some way, I do think the Vault's DAC is more likely the cause as it renders some of my ripped CD's with a presentation that's a bit more forward and lean than I remember. Will try Tom's suggestion on listening height this weekend as I also swapped out my old listening chair just before getting the MIT cables and Vault 2 installed.
Happy listening!
Arvin C