No kidding? He replaced the Bose HU? Or did he have a Mazda HU? I had thought that the Bose was standard but perhaps it was just standard with the package that I purchased. If he did have a Bose, is the Pioneer unit that he selected significantly better?

I see. The P-BUS connector let him connect the RCA cables off of the Empeg harness? And the other end of the P-BUS plugged into the Pioneer HU, right?

Just trying to ascertain all of this ASAP as I was contemplating a new head unit for the above reasons.