Upgrade suggestions from BAT VK-300xSE

I'm leaning towards the BAT VK-31SE (good deals on out-going model) & BAT VK-250, which I will demo. this week, though it won't be cheap at $12K-retail (2X the cost of my VK-300xSE). I'd rather not mix-and-match pre-amps & amps. Manufacturers of this caliber go through a painstaking process when voicing (tuning) these components for optimal mating, and I doubt that I could better. The ARC LS25MKII & ARC VT100MKIII are my second choice, at around $5.5K-used, though I’m hesitant to take on the bulk, heat & maintenance of a very large tube amplifier.

The last time I checked, a VT-100 factory retube (power tubes only) from a dealer costs $850.
This is every two years if amp used daily (1-2 hours) and weekends (4-6 hours).
You can use non-factory tubes, which go for around $400,
and bias yourself.
This is partly why I switched to SS.

i ran a 300xse with my sophias...then stepped up to 31SE/75SE. whole different league at that point. 51SE was an even greater improvement.

good luck!