Ok, finished the installation.
First of all, the connector issue mentioned above, was easily resolved with 3.5" floppy drive power connector grabbed from some old PC power supply. It doesn't fit exactly but is close enough so it fits with very minor cutting with a carpet knife. The result fits so tightly that I'm not sure if it's possible to remove it anymore.
With this trick, you don't need this harness mentioned in the OP:
"
1032431-00-E - Wiring harness - $60. You are only buying this harness for the connection that matches up to the USB converter"
Then I removed my old console. I compared my original frame (right) to the new frame from 2019 Model X (left):
As seen above, there are a few differences. Model X frame has a rectangular hole in front, for the sliding door to slide through. Model S part has much larger "flanges" in the front section. So my choices were, either to cut the rectangular hole to my old frame, or use the MX part and ignore the obvious difference in the shape.
I chose the latter! I looked very carefully and I think it's only missing one support point for the "kick panel" that attaches to this center console frame. And being made from flexible plastic, I doubt it actually even gives that much support? Anyway it worked out very well with the MX part.
However if you don't buy the entire console, you probably need to modify your existing frame to have the big hole in the front.
Then, I noticed another problem. In previous page
@TheFro mentions you need part, 1064478-00-B air duct. Turns out this part is completely different shaped in MX, so the part included in my "complete" console was unusable.
The old style MS console has much longer air pipe that goes directly from the floor to the rear vents. New console has much shorter piece that only connects to the plastic support bracket 1057331-00-E. So I figured I just cut the old duct to proper length:
Well, it certainly did not work out too well.
The hole in 1057331-00-E is very different in shape, as seen here:
The air duct is very soft material, and easy to cut with scissors and knife, and also can be reshaped with a heat gun. After a while I had it installed reasonably well:
Then I taped it with aluminum tape so there are no holes:
So it was a bit of a work, but again avoided buying more parts and especially allowed me to finish this project today.
Then I added wires for the +12V supply to the rear USBs. I soldered and shrink wrapped them.. The grey connector is the one that goes to the cigarette lighter. I removed the pins from the connector so I could solder the wires without cutting the original wire.
And well, that's it, then it was just reassembly. Few pictures of the finished product, except for the sliding door lid that I haven't yet received from the SC. Sorry for the dirt..
Oh, the MX rear panel around the air duct had "graphite" surroundings but my car has chrome in other places. I transferred the chrome part from my old console to this one. Also the arm rests and upper trim are obviously from my old console because MX had different color.