Hi Rainsey, seems strange your speedo is out but odometer is correct, have checked mine against GPS - all OK.
One Redarc gauge for oil pressure, coolant temp and temp probe on the top of the intercooler where I have fitted a thermatic fan to help bring the temps down on slow going tracks - no use when speed is above 50kph.
Regarding your coolant temps try blocking the gaps around the front edges - sides and top of your radiator (Clark Rubber) I found it did make a difference, also as mentioned in previous responses large driving lights and winch control boxes will impede air flow dramatically. If you are down my way some time we could meet up and compare notes.

regards

Peter