my first suggestion would be to go to radio shack and pick up the necessary length(or two runs , running it in stereo if your worried about impedence) of their more than descent "gold ended" audio cable.
I would bet you that you get more than satisfactory results.
Really 99% off your sound challenges now should be getting the sub set up correctly(which most people don't do right!) and getting it matched to the mains from your seating possition!
I can't tell you how many people, even exerience audiphiles, can't set up a subwoofer well! It's the single most worse set up speaker usually for people! Since bass is the most critically location dependent factor for a speaker, it's also the most universally improperly done!
Spend time learning how to get your sub set-up right(as well as the rest of the speakres, which no one does right either) and you'll pretty much forget about trying to play "cable wars" with your sub cable!!!
I can take anyone's multi thousand dollar audiophile sub, with the most expensive interconnects money can buy, and can stil outperform their setup in any given room, using much less costly gear, simply because I know what I'm doing!
good luck
