You answered your own question because they obviously do make a difference. The unfortunate thing is that you never know how a cable will sound in your system until you implement it. Good for you though, because your post conveys your happiness in finding a cable that delivers the type of sound that pleases you. As someone else said, the S1 Interconnects are also special!!
Do speaker cables really matter?
Hell yes!
Been running a double run of Kimber 8TC from SimAudio W-6 monoblocks to my Aerial Acoustics Model 9 speakers. Had for a few months wondered if the speaker cable was the weakest link in my system at this point. Really struggled with the question speaker cable really mattered or is it all snake oil? I'm here to say, "It matters. It really, really matters!"
Picked up a pair of MIT Shotgun S1 bi-wire (thanks, Joe!) and switched them out yesterday. Wow! My system is blowing up! I thought Aerial had simply rolled off the highest of the highs. No, they were there all the time but the 8TC was 'veiling' it. Also, they speakers have become slightly more forward, which is a good thing. Overall improvement up and down the scale. Soundstage has increased dramatically. Almost sounds as if a bedsheet has been sitting over my speakers the last few months and now it's been removed. They hairs on my arms lift up when listening, now. I truly didn't think it would make such a difference and thought I would post that it did. It really did. Can't imagine what will happen as they break in.
I hope posting this helps a few members who are sitting on the fence. Was considering The Cable Company library to try a few but didn't want to wait. Too impatient.