Very interesting link Wayne proving I am way behind the curve in my knowledge of crossover caps. Years ago, I thought Tantulum Pentoxide caps (back to back for non polarized) were satisfactory. I am glad I changed them out. I suspect I am also way behind the curve regarding speaker wire. At first glance, the expensive cable looks like a sales gimmick. I may also have questionable hearing as I can't tell the difference between cheap 14 gauge stranded copper wire and Monster cable.
I only see a few pico-farads per foot, DC resistance and current handling capacity as being important...but what do I know.