I've used, and seriously compared, Stealth CWC (a copper litz wire design), Stealth silver ribbon, and Stealth PGS.
(Disclaimer: I know the designer personally, though through a wire purchase originally, and wish his company success, so discount my opinions if you like.) In my system, DIY passive preamp, Atma-Sphere M60 II power amps, Quad ESL 63 speakers, the PGS is the most natural-sounding IC I've ever heard, by a wide margin. At first I thought there was less detail than with Stealth silver ribbon, then I realized it was there but just not as highlighted. Since you can try these cables with a 30-day money-back guarantee, I'd give PGS a try.
(Disclaimer: I know the designer personally, though through a wire purchase originally, and wish his company success, so discount my opinions if you like.) In my system, DIY passive preamp, Atma-Sphere M60 II power amps, Quad ESL 63 speakers, the PGS is the most natural-sounding IC I've ever heard, by a wide margin. At first I thought there was less detail than with Stealth silver ribbon, then I realized it was there but just not as highlighted. Since you can try these cables with a 30-day money-back guarantee, I'd give PGS a try.