Engine-water temperature sensor threads??

[schlumpf]

I would also say that the overtemperature LED is useless. The more as you now install a real meter. Take the "switch thread" for your new sensor.
In case your gauge supplier also offers/recommends a proper temperature sensor go for it. Otherwise you might end up with false readings as there are millions of different sensors on the market, most if them incompatible.
Or does your gauge has settings options for the sensor type?