Signal Cable REL cable vs Speakon Custom REL 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.