[notorious]

Could you please explain the problem you're trying to solve? I understand it that on non-BOSE car parcel shelf speakers don't work.

If this is the problem why you're trying to change the RNS-D? If you need to change RNS-D to solve other non-related problem I'd finish with that problem and then I'd code RNS-D for non-BOSE properly and then check wiring for amplified rear shelf speakers. I'd trace each pin on the back of RNS-D to amplifiers.

No disrespect, but I'd also stop reading anything but ELSA. All other sources are unreliable. See attached PDFed wiring diagram for RNS-D for 2002 cars. Just study what pins on the back of RNS-D are involved in non-bose setup. Then understand who amplifies what. And then do experiments.