Hi all, I took the plunge & replaced the stock head unit (which in my personal opinion was awful).
Since the process went well, I thought I would share my experiences here, should any of you be interested in doing something similar. Total cost to me was R5000 including shipping costs.
The unit I got my hands on is the Zestech PX6 - 4GB RAM, 64GB ROM, 10.1" IPS display. Part of the wiring harness includes two usb cables. You can find this PX6 unit on Alibaba.
Features I have tested & can confirm works:
1) Bluetooth, I have imported the phonebook & made calls
2) GPS - Installed Sygic (the head unit comes with a small external gps as it cannot connect directly to the Hilux factory GPS)
3) Android Auto, Automate, etc (really cool applications to use as a launcher for the unit)
4) WiFi connection (I believe that you can use a 3G modem with this unit as well)
I am still trying to investigate how to view vehicle stats on the new head unit (similar to how the stock unit does range & economy), this is by no means a critical feature.
I will be testing android screen mirroring as the unit is capable of this, both wirelessly as well as USB.
This hardware installation is pretty much plug & play (no need to cut or splice an wires), there are wiring harnesses with a bunch of extra connectors. You would just need to connect:
1) The AUX cables together
2) Camera to REV-V
3) Canbus box to the head unit connector
4) Steering buttons are mapped to the unit software (via a learning application - easy to do)
5) Remaining standard connectors to the Hilux (power,etc)
I believe there is a way to get the OEM GPS to connect, one would just need to figure out what connector to use.
See attached pics...