It works, but not great. For short runs in a car, not a big deal, long runs in a house, the impedance is wrong and you get signal loss. Also, Coax is designed for the 2 GHz area (+or-), we're MUCH lower frequency. Also, coax is not twisted, which means no noise rejection. That's my point, coax is the proper diameter for frequencies in the GHz range, we are in the kHz and down range and the same diameter. The wavelength is physically longer. 100 Hz about 3.5meters, 25 kHz 1.3cm, and 2 MHz is in between 1mm and 2mm. 2 GHz is VERY small physical length.

As far as you hearing a difference, I would put money on the fact that it was either placebo effect, or the new ones were twisted. Keep in mind different twists/more twists make a difference.

Rockford Fosgate used to have great rca's that were braided with a third wire (that had no copper, just insulation). These were excellent as they rejected noise because they crossed back and forth, but they didn't twist around each other (this was to help with the whole balance between inductance and capacitance of twisting pairs of wire).