Thank you, Mercedes for ushering into existence the needlessly complicated Becker 1492 Active Bass System. I think it was cobbled together by Engineers freebasing the nightmares of children mixed that black powdery mess found between Satan's toes.
Like many, the Becker system in my 91 300D was on the fritz. I had zero intention of spending the $300+ to have it refurbed and upgraded. So I picked up a Kenwood Media Receiver (KMM-BT322U) and patched it in. It took me several hours to run wire, patch in, blah, blah only to find out the front right speaker was consistently cutting out.
Knowing the options are limited as to speakers, I sprung for these on Amazon:
https://www.amazon.com/gp/product/B00MX404SO/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
I'm hopeful, this thread will turn into a positive review of this kit... stay tuned.