Which SS integrated amp to choose?

Luxman owner here. Two others you should listen to are Arcam and Ayre.

     I don’t own one but extensively heard the Mark Levinson 5805 integrated at a local hi-end shop driving both Magico and Sonus Faber speakers. It sounded so good that I bought a fairly expensive pre-owned ML 326S preamp just to try and capture some of the 5805's excellent qualities in my system, I was told the 5805 basically incorporated the 326S as its preamp section. It worked like a charm even though I use high powered class D mono-block amps and Magnepan 3.7i speakers in my system.
     The main qualities I was attracted to were the 5805’s very well defined 3 dimensional soundstage it presented, its high levels of neutrality and detail along with its palpable and natural perception that the musicians were in the room, or being transported to the venue, depending on the recording. 
     However, it may not be warm enough for your tastes and pre-owned prices are likely well beyond $2K. But it matches your power and weight requirements and it sounds spectacular.

Tim

You should take a look at the Aesthetic Mimas. It's the most musical integrated amplifier I have ever heard. I liked it much better than the Luxman with my speakers, Harbeth Super HL5+. You should try to hear it with your speakers though. Good Luck!