In all honesty, that "crap" 18 gauge wire is probably not as bad as you think, but it could still stand to be replaced.
If I were you, I'd take all the cable marketing/propaganda with a grain of salt and consider going with genereic 12 gauge wire. There has never been ANY solid, repeatable evidence that speaker cables make a noticeable difference in how speakers sound.
The Phoenix Gold 12-gauge sells for about $.45/foot. You can get a much better deal on blue 12-gauge wire. I found a deal on a 250-foot spool
here that works out to about $.17/foot.
