I received and installed my Auva 70's yesterday. I was amazed. I expected maybe some improvement but not to the extend of what I heard it was transformative. It's crazy that just placing those under your speakers could do this.
I have more depth to the sound stage, sound stage is larger, cymbals hang longer with slower decay, more presence or whatever that is that fools you into believing the music is closer to live, I get more of a sense of rhythm and the melody. Bass is more tuneful but slightly leaner maybe. A review says the bass comes back after about a day once the particles inside the Auva settle. I'll have to comment on this later I haven't had the system on yet today. Even it if bass didn't fill out more the improvement is so good I wouldn't care.
I highly give my recommendation as a tweak that really works, and well.