No problem. Also an expert may chime in here, but I’m pretty sure if you disconnect the ECU temperature sensor - the car is going to act really wonky. I believe the ECU needs it to calibrate things.
@VR Thor is the man. I would add...if you buy an aftermarket gauge, it frequently comes with or you have to buy the corresponding sensor/thermistor for it. The gauge uses the thermistor resistance which changes with temperature to determine the needle position on the gauge. Different gauges use different thermistors and their ohms resistance range is different. So if you intend using your stock sensor, be sure the new gauge uses the same X ohms = Y temperature scaling. I can't see below the hose in your picture, but I believe you will find a third port to the left of the other two sensors that is sealed with a removable threaded metal cap. You can add the new gauge/sensor there, and keep the stock setup in place.
