Anyone use the following sub interconnects? Could you tell us your experience with these cables and how it enhanced the sonics of your subwoofer? I'm currently shopping one for a friend (i have yet to have a subwoofer for my own system):

Bettercables Silver Serpent
http://www.bettercables.com/silsersubcab.html

ZBass100 Audiophile Powered Subwoofer Interconnect
http://www.monstercable.com/productPage.asp?pin=911

M Series® Bass 1000 Powered Subwoofer Interconnect
http://www.monstercable.com/productPage.asp?pin=1206

Rivercable Starflex
http://www.rivercable.com/subwoofr.html

Analysis Plus Sub Oval
http://www.analysis-plus.com/Pages/interconnects.htm

Cobalt Cable Ultimate Subwoofer cable
http://www.cobaltcable.com/product/subwoofer_cable.htm

DH Labs Sub Sonic
http://www.audioc.com/accessories/subsths.htm

not to mention the ones offerred by JPS Labs and Cat Cables. Thanks in advance.