I just finished fitting a Joying head unit in my MY2017 BRZ. The head unit is their model JY-UO128N4G.
The cable harness I used it the Hilux one, this connected with everything and did not need any modification
Hilux harness
The Starlink in this model BRZ has a trapeze shape which makes life a little more difficult
There is an adaptor available but it turns out it is for a 'different' universal size hole - how many universal sizes are there???
My solution was to print my own with a 3d printer. The result is more than satisfactory and it fits both the head unit and dashboard hole perfectly. The hole dimensions are 100.5 * 179 and it also fits nicely on other Chinese head units. You can download the design here:
BRZ Audio
At the same time I installed a rear view camera which I obtained here:
Rear view camera