Wilson Audio Sasha I or 2 ?

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.  

@mmbl622 Hello there...what did you decide on?  I have Sophia 1 with ARC REF gear and am getting the itch to upgrade.  I heard some Sasha 1 at a friends house and was very impressed.  He has modest SS gear, don't recall brands.  I really wanted Alexia 1 but ARC said that's a bad idea as all that's written about their load is correct and my REF75SE will not be happy.  

i am thinking on buying again wilson; i had sabrinas, but was not able to make them really sing in my room, especially in the bass area - 14x18x9 feet; now i have better suited amp (diablo 120)

do you think sasha 1 will be ok for my room? or should i look for sophia 3 or yvette?

now i have revel F228be, and they sing ok, but i liked a little bit more the vocals/midrange of sabrinas

I think the Sasha will be fine if your room and the wilson I would chose for that size. It will have much better and stronger bass extention than the 228be (which I have owned).