Parts List

PSU to Board:

Wire: https://www.amazon.com/dp/B08HSC5NW5

Connectors: https://www.amazon.com/dp/B08HK1Q4F6

Crimp tool: https://www.amazon.com/dp/B00079LN1Y

You can get away with 14 gauge steel wire I believe but going thicker just makes things a bit safer with this kind of amperage. The connector kit is overkill too but I can't remeber which size I needed. I do remember having to trim the sides of the connector rings to fit inside the terminal space. You don't have to use connectors at all but it gives a more secure connection. You can get away with directly clamping the wire under the terminal screws if you prefer though.

3 pin to 2 pin adaptors

3 pin: https://www.amazon.com/dp/B01DUC1PGC

2 pin: https://www.amazon.com/dp/B09KH68WVL

I just solder the wires and put some heat shrink on them so I didn't have to change any of the factory wires.

Dual z wire for second stepper

https://www.amazon.com/dp/B0823QJJ8C

Optional fan upgrades

Board fan: https://www.amazon.com/dp/B07CG2PGY6

Heat block fan: https://www.amazon.com/dp/B009NQLT0M

The octopus can run fans at multiple voltages so you can swap the factory fans for quieter more efficient nauctua fans. The heat block fan came with an adaptor but I had to rig one for the board. I just can't remember how I did it. That said, you may end up needing a different board fan depending on the enclosure you print.

You need to print a board enclosure and PSU enclosure since the wires don't fit through the factory enclosures properly. I can point you to the stl files I used if you want.