Would like to upgrade amplifier and would appreciate suggestions.

Hello,
I just upgraded my Zesto Andros 1.2 phonostage to the new Andros Deluxe 2 and very happy with that.
I have the Zesto Leto 1.5 preamp, and will do one of the following:
    Have the power supplies upgraded on the Leto 1.5...this would be the least expensive.
    Trade it in for the new model, Leto Ultra 2
    Or, if need be, sell/replace with best compatible preamp for whatever amp I upgrade too.
Zesto preamp specs:
" 3 pairs transformer-coupled balanced (XLR), input impedance 10k ohms; 3 pairs single-ended (RCA), input impedance 100k ohms. Outputs: 2 pairs transformer-coupled balanced (XLR), output impedance 150 ohms; 2 pair single-ended (RCA), output impedance 150 ohms. Maximum input level: 7V. Maximum peak output level: 10V. Frequency range: 10Hz–40kHz. THD+N: 0.03% with 1V RMS input. S/N ratio: 100dB below operating level. Gain settings: 9dB, 6dB, 3dB"

My present amp, is a pair of QuickSilver V4 mono blocks, these are the newer version built around the KT150 tube and rated @ 170 watts.

My current speakers are Green Mountain Audio Continuum 3...which in a year or so I plan to upgrade those too as, even though they have low hours/like new, they are aged.

I'm thinking that if I buy hi-quality used gear, I will get much more for my $$.
For an amplifier, I would like to keep it under/around $10K and if needing also to spend on a preamp, it should be under/around $8K.

I love tubes, have had nice solid state in the past too... such as an Edge NL12.1 amp.

Looking for the best sound and also some power, so would like around 200 watt output... unless it is an outstanding amp that a little less power is still worthwhile.

Was looking at Audio Research stuff, but not sure if compatible to what I have already... there is so much out there and I have not kept up with the hobby over the past 15 years or so....

Your comments and suggestions are very much appreciated!

Rick