Originally Posted by ppro

Thanks for the informed response. Your points validate what I have observed in actual practice. An interesting side note is the behavior of my stereo in my Jeep Commander Overland which has the factory entertainment system with DVD player. When using the RCA inputs, it takes a few seconds for the head unit to "see" program material coming in. It won't allow selection of the AUX channel until it gets signal on those inputs. What's even more interesting is that in between songs, it often "goes away" because no signal is detected. Once the song starts, it takes a second or more to come back in. It's a "better than nothing" solution.

I found the harmann/kardonn Drive+Play inline antenna-connected FM approach was barely better than nothing. The radio still detected outside broadcast sources and was a very noisy solution. The broadcast FM modulation was hopeless - going to your point about the strength of the signal it puts out - probably compliant with FCC regs and weak. My Roady XT XM radio seemed to have a lot better performance rebroadcasting the signal - never had the problems maybe because it was over the power limit specified by the FCC....

So I wonder if plugging into the RCA lines of the CD-changer on the NAV unit would give the same results as my Commander - an input stream that the head unit "sees" as long as it detects a signal? From what you're saying, that would require the additional unit (which was my conclusion). Given that, the cost involved really does suggest a better value proposition is to go with a new head unit (higher end sound, more flexibility, XM, iPod, MP3/AAC etc compatibility)... I rest my case...