Chevelle -- right now, if I were you, I would put my money into
better speakers, then better CD player, then better Amp. After you've made those upgrades -- on your next round of purchases,
I would look into a nice AC Conditioner. Take all the money you want to spend on Subwoofer, high end cables, AC Conditioner
and put it into your speakers and then CD player and then amp -- you'll get a much bigger improvement in sound than putting all those expensive accessories on your present system.