Those svs isolators worth the money for sub. I bought them to try on my m&k x12 and immediate notice was that it took away the sub localisation factor. Now the sub have disappeared , as if now the low freq is coming from the front rather than side wall where the sub is physically located.
Apart from that I have got isoacoustics various isolators under my amp, streamer/dac and speakers . I picked up used and real cheap to try them myself . Did AB comparision and didn’t hear anything difference applying to amps or dacs or BD players - except for the speakers where I felt have improved the soundstage a bit . It could be a placebo effect as well.
I have kept the isolators just because they look cool, expensive and few components where they stack on top of another got some room for air movement