NAGRA VPA monoblocks

I am looking to buy the Nagra VPA monoblocks, wanted to know the experiences that other owners had.

I have the Amphion Xenon's for speakers. I use transparent reference mm cables for interconnects and speaker. Shunyata V-RAY and shunyata anaconda helix and anaconda matrix power cables, I have T + A tube pre-amp and tube CD player.

please provide your inputs and exoeriences with any setup that you have with NAGRA