HP to HK Sound: Door Wires

[IMAY2023]

It all depends on the donor car from which you are getting the AUD. 
If you get it from 90 series, you will need to wire the MIDs and Tweeters on the rear doors from the AUD to the speakers because tweeter + MID (in Parallel ) have secondary output channel (MID+high) on the AUD.  

If you get your AUD from a 60 series, then you just need to wire the tweeter and MID parallel to woofer inside the door. 

For the part numbers, 
it all depends on what you have right now. 
Usually, the harness on the trim panel already has the MID and tweeter connectors but the harness inside the door does not. 
Sometimes depending on the production week, the doors are pre-wired but you still need to wire from the AUD to the door connector. 

I upgraded my s60 from HK to BW of 90 series. So, I had to wire the MIDs + Highs per each door. 
I bought 1 used internal rear door harness and got the 4 little male pins from it.  From the AUD to the door harness connector. I could not find the part number for the pins or repair terminal. So, I pushed the wires directly into wholes and tied to the rest. It works and I never had issues. 

It's not high amp connection, just a speaker.

Interesting! My V90 (MY2018) with the HP system came with just the woofers on the back door. But according to the wiring diagram, and counting the number of connections on the back of the AUD, the rear door woofers are wired in parallel with mid-range speakers mounted in the ceiling near the d pillars. My understanding is that these ceiling d pillar mids were then moved to the rear door in MY2019.

Best I can tell the difference in speaker count between the HP and HK systems in the V90 is they added the center channel, subwoofer, and then the rear doors have a tweeter, and the d pillars have midranges.

So I think I need to add the tweeters to the rear doors and then separate/un-parallel wire the rear door woofers and the d pillar mids since the HK AUD has separate connections for each. Does this sound right?

I seems, V90 and S90 have different layout on the rear door speakers. S90 series have (Woofer,  MID + Tweeter) being MID and Tweeter in parallel.  
As I mentioned earlier,  the output channels of the AUD will depend on the donor car model. Don't get confused; the part number is same for all models. The difference is the configuration file inside the AUD which is uploaded during the reload process which must match to the installed software.  Which will dictate if you need rewiring or not.  Check the enclosed full wiring diagram for  S90 and V90.  Search for 7A External Amplifier, you will see different variants.