SET amp comparable to First Watt SIT 1?

I’m currently planning to change my speakers to high efficiency horn from modern high end speakers (B&W). The speakers would be Volti horn speakers.

For amp, A friend of mine has First Watt SIT-1, which sounds great to my ears, but I have always been interested in tube SET, especially 300B. The problem is there are too many choices around, and I have read several online reviewers stated that 300B amps don’t sound as good as First Watt SIT 1, except extremely expensive ones with NOS WE300B.

Any suggestions?

My budget is around 7-15K. I don’t mind second hand ones, but I wish I could compare it with my friend’s SIT 1 before I decide to take it or not, so second hand unit is probably not an option.