I just read this thread. There are many companies selling upgraded cables. Some of these make sense, others are, well snake oil. The use of litz type wire in speaker cables to reduce 'skin effect' for better high frequency response is one laugher. While skin effect is real, it generally doesn't make any difference until you reach several MEGAHERTZ! The most important thing you want in speaker cable is low resistance, especially with 4 ohm speakers.
So a friend of mine wired his speakers up with #10-2 romex! PS. they sounded great.