Embarassing electrical question

Considering that i always hated physics in school i have this silly question, but first let me explain.While upgrading female RCAs on my cd player to WBT Nextgens,i encountered a wiring configuration where a positive wire was soldered to a connector and the ground was connected via a figure 8 washer to both female rcas.Nexgen being a plastic body i figured i cannot replicate the same thing so i called WBT for an advice.I was told that i can connect the ground by the way of soldering any cheap wire that i can find in my house and that it would in no way affect the sound.My question is:does it work the same way for the speakers in a way that i can upgrade only the positive binding post and leave the other one untouched?Please,explain.
No! no one would ever do that! The negative speaker post is not the same as the common ground on the input RCA's.

What would you do then -- use only the positive leg of some really exotic speaker cables and RadioShack 16-gauge for the Negative leg? It just doesn't make sense.
I currently have WBT Midline binding posts and i thought i can just install one WBT Signature post on each speaker and keep the other one Midline.
Well, you can do that if you want, and it will work -- it just wouldn't be the best approach... I've never heard of anyone mismatching speaker binding posts.
Would you use better tires on one side of your car if all you did was turn that way?
That's exactly what NASCAR does, so mabbe that is not so far fetched!