I presume you are aware, but if not:
I still have AN Kit 3 monoblocks and AN Preamp Kit,bought and assembled in 1998.
I also have current AN Kits PSE 300B monoblocks and L3 preamp with a really extreme upgrades.
The Kit 3 monoblocks without any upgrades are great sounding amps,my friends were dissapointed with their EAR and Audio Research tube amps after connecting my AN Kit3 amps in their system.
Now I've decided to bring them on a higher level,I just received almost all upgrade parts like all Tantalum resistors,AN Copper Foil caps,Mundorf caps,AN silver speaker and RCA terminals,AN silver valve bases,AN silver wire,silver turret tag boards and so on.
I'll make them completely hard wired with the silver wire even for a power supply.
It costs much,but they are worth it.I made my decision after
hearing all this years many, so called "high end" amps.
They were only "high priced" compared to my Audio Note Kit 3 monoblocks (designed in Kondo-san era).
There was one pair for sale a year ago on web,maybe it will appear again,just keep looking.
Regards from Croatia,