Slowhand,
No, I would not say the V-Caps changed the tonality of the Supratek in my experience.
Yes, I would say the V-Caps are considerably more detailed. That does not mean analytical and cold, but rather much more invisible. It seems to me that whatever the signal is in front of the V-Caps, it comes through much more pure. If you have warmth in the signal path prior to the V-Caps, you will get a cleaner, less congested warmth and I am sure if your system is cooler or more analytical, you will get a purer sense of that, as well.
I think "invisible" more accurately describes the V-Cap.