Well, I will only speak to the balanced part. If you are not stringing wire from down the block immersed in strong electric fields there is nothing balanced wire will do for you. You are spending money to fix a problem you do not have. Pros use it because they string so much wire through areas having tons of electronics in it and a balanced system can get a clean signal even if the noise signals are greater than the amplitude of the signal. This is not a problem in residential systems. Balanced line has the pro mystic because pros have a use for it and people demand it and there is a market for it. As Abe noted many amps that accept balanced line do even have the circuitry for it (looks cool though)! If the XLR would somehow be better for another reason I cannot say. There are plenty of real improvements to make in any system, eh?
Balanced cords will not improve your base, at least i have never encountered that claim although the way wire is marketed I would not be surprised to hear it.
Sincerely, I remain