Well, technically speaking, only the Mars and Horus are gold-plated silver. The Leonidas is a gold-silver hybrid. The Horus is a successor to the Mars with EA's multi-size-strand technology (where the strands within each wire are different sizes) among other improvements. Based on my experience, the Mars is actually more similar to the Leo than it is to the Horus. Both have a rather full-bodied sound with a rumbly bass response, rich lower midrange, sparkly upper midrange, and smooth treble. However, where the Mars differs from the Leo is in the upper registers. The Mars carries more energy and extends further in the treble, where it is noticeably more transparent than the Leo. The Horus on the other hand, is technically far superior to either cable and carries a sound signature that's closer to neutral than it is to natural. The Horus has an accentuated bass response with gorgeous physicality and texture, with layering, depth and rumble that neither of its brethren can touch. Its midrange is leaner and more crisp, providing superior clarity and transparency at the cost of pure naturalness; it relies on the IEM having a natural midrange to compensate for this. The Horus's treble is insanely resolving, unrivalled in extension, yet smooth as a baby's bottom as well. As I said in my Horus impressions, its treble reminds me of the A18's treble, where it's extremely airy, clean, clear, crisp and extended, yet never harsh, unpleasant or strident. Unfortunately, this is all I'm able to share based on memory, as I don't have either of these cables within my immediate vicinity. But, I hope these impressions can at least give you an idea of what each of them can do for your IEMs.