Signal Cable REL cable vs Speakon Custom REL cable

When I first bought my Rel Stadium 2 almost 15 yrs ago I swapped the stock cable for the Signal Cable and noticed a faster, cleaner, deeper extension and was pleased with the improvement to cost ratio. I have also played with power cords ranging from the Signal Cable to VH Audio Flavor 4 to several others. Overall, no matter which speakers I combine the Rel to it is always a significant improvement in image presence and soundstaging...this is regardless of how deep the main speakers extend. I will almost go so far as to say the presence of the Rel adds benefits to practically any speaker system it can be properly integrated to. It's that profound. For the record, my speakers, all of which have found the improvement were/are:
Martin Logan Aerius I's, Audio Physic Tempo 3's, Silverline SR-11's and 17's (mini monitors naturally appreciate the Rel), Silverline Sonata 2's (essentially full range...almost) Apogee Mini Grands (already with built-in subs) and currently my fully rebuilt (by True Sound Works) Apogee Duetta Signatures...
Every instance was noticeably improved...Rel subs are a wonder...well worth it, IMHO. Good luck

Does anyone have an answer to Louisl's original question? I too would like to know what everyone thinks of the differences between the Signal and zikhmark's cable.

Since the original post included an "or", I think at least that part of the "original question" was covered. Again...you can avoid silly REL cable mythology and expense by easily building your own (multiples even) with whatever you like and comparing the results yourself.

I purchased a REL subwoofer cable from Mark Zikhmark to replace my diy cable I was not happy with. Mark cable is good, very good. Bass is tight and deep, seamlessly integrated with the rest.
When using my diy cable the soundstage had more "air", there was more spatial info , the soundstage was more open but at the same time I was losing some images density and clarity.
It's not the case with Mark's cable. Soundstage is more open, with more "air" and the clarity is there, images density is "preserved". Dynamics has improved as well. I enjoy the system with the sub more then without it now. I can recommend Mark cable, a good investment.

My new-ish REL cable lowers the dust content of my listening room, and has made me a much better person.