Sound quality is important to me for my car, and I am going to buy either the Pioneer Avic-x930bt or Avic-z130bt in-dash nav head unit. The units seem almost identical in their specs as it relates to putting out sound, except the x930 has 2V preout and the z130 has 4V preout. Also the preout impedance for the x930 is 1k Ohm and the z130 is 100 Ohm. Does this mean the z130 is built to push better sound to my amp?

What is the difference in real life between these two devices? Is there really better hardware in the z130 model? What's the scoop? Bottom line question...Is the z130 model going to give me a better sound signal output than the x930 or will they be the same? Why or why not? Is there a difference? And please don't generically say "ya, they'll sound about the same." Why are the two units labelled with different specs in this regard? Thanks