Wilson Audio Sasha I or 2 ?

I am now listening to Wilson Audio Sophia 3 with Audio Research Ref 6 preamp and Pass Labs X-350.8 amp.  I love WA speaker’s sound and I'm considering an upgrade of my Sophia 3 to either Sasha 1 or Sasha 2. For sure, if I choose a used Sasha 1, I can pay much less than Sasha 2 (both used and new). Someone said Sasha 1 sound very close to Sasha 2. Unfortunately, I have no chance to compare all these speakers side by side. Looking for advice on (1) How far of sound quality compare with Sasha I & 2? (2) What are the main difference of sound quality between Sophia 3 & Sasha (1 & 2)? Thanks.

The Sasha 2 to my ears was only marginally better than the Sasha. If the overall difference was 10 percent, I would be surprised. I cannot pinpoint a specific area where the Sasha 2 was significantly better, although someone who has owned both might be better qualified to answer that one.
The cost used, however is about a 33 percent differential.  Both are bargains at used prices but especially the Sasha which should cost in the range of 12k used in excellent condition--frankly a ridiculous sum for a speaker of such outstanding quality. So, ultimately it is a question of how much you are willing to pay for that degree of improvement. The law of diminishing returns applies, a law which I have consistently violated in my audio purchasing career. BTW, I have owned Sophias, WP7s, Sashas and now Alexia2s with all ARC reference equipment during ownership of all.