I have a 15$ Bluetooth obd2 adapter and torque app and my fans kick on like clockwork when the coolant temp reaches 96c.. Usually doesn't reach this from just idling... I have to drive around for a bit then stop and idle and it starts creeping up . Then the fans kick on and take it down to about 89/90. Pretty sure this is standard on all WRX's. Not sure if the Bluetooth obd2 things work with gc8's too.

Also worth mentioning the temperature gauge in these cars is not exactly a good measure of if your car is running too hot or cold. Mine will sit at "normal" between about 70 to 100.That's why I love using the Bluetooth adapter.