I got the connectors in on Thursday as expected. I examined them and decided to use these:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
For my modifications (explained in post #79), I'm going to cut 4 wires in the vehicle harness. I'm also concerned about breaking the BMW pins we inserted into the Maxhaust "Blue" connector. Since I'm going to cut the harness anyway to solder in my wiring, I figured I might as well do it while the BMW pins were still inserted into the Maxhaust connectors. This way, I could then take the harness up to my workbench and have lots of light and a good selection of tools to extract the pins from the Maxhaust connectors (instead of trying to do it while bent over the trunk).
I pretty much surgically destroyed the Maxhaust Blue connector so I could be sure I could get the "BMW" pins out without breaking them. I wasn't going to reuse that connector anyway... (Success!)
I wired together my harness with some spare suitably sized wire I had laying around. I was able to match the Red (+), Black (-), Blue (CANBUS Lo), and White (CANBUS Hi) Wires. The other four colors I just chose at random (but duly noted).
After I finished the connector to graft into the cars harness, I cut down and rebuilt the Maxhaust harness. I also built my BMW "Loopback" connector.
Everything works great! (Whew!) I can now choose whether I want to use the Maxhaust Sound Module or factory BMW Sound just by changing whats plugged in via a SINGLE connector. The BMW "Loopback" connector is also very easy to just tuck back inside the little cavity behind the fuzzy door panel.
I don't know why Maxhaust used TWO connectors to connect to our cars when a single connector would work just fine. That horrible blue connector even had many holes to spare!
Anyway, I think this is the way they should have done it in the first place. I understand why they wanted folks to extract those 4 pins from the BMW connector (so nothing had to be spliced or soldered), but this modification provides a much more functional, convenient, and flexible solution.
Now all I have to do is wait for my Maserati Sound Module to arrive! I'll be sure to update this thread at that time. Its should have already shipped and I expect it might be here by the end of the week!
I'm particularly anxious to compare the Sound Quality of the Maserati Module vs the Maxhaust Module.
The photos below show the Maxhaust sound module and bluetooth unit on the floor of the trunk (and in the little cubby). I used to have them mounted behind the rear trim panel, but I don't see much point permanently mounting them (yet) if there is a good chance I might switch to to the Maserati Sound Module.
Stay Tuned!