Bob:
Thanks for the in depth reply.

So you are saying that the speakers that were removed were NOT dual coil, and that instead, some wiring got "damaged/broken/etc" in the install of the new speakers..?

I should mention that I had (and still have) a BSW sub with a Rockford amp that WAS working with the old phone and ULF.

It's a "mission" for me to pull out the radio and take photos, so if there is a way to avoid that, that would be good. It's a stock BMW Business HU if that means anything.

Given that I am really to trying to provide my installer with some insights, is there anything that could be done SIMPLY to add the speaker as you described..? My buddy that helped with the TCU install, seemed to think (although we did not remove the door panels) that it might be possible to pick up the signal from the door harness, and simply install a speaker by the gong as you mentioned... Things that don't sound simple to me..

Lastly, given your obvious expertise, is there a likely suspect that my installer may have inadvertently corrupted given the description of the brand / location of the speakers we replaced (mid bass with a crossover to the original tweeters).

Many thanks...

ed