Actually running without a thermostat would make little difference during hot weather or strenuous driving. The engine temperature is mainly controlled by the fans and the efficiency of the radiator (I.E. I heard somewhere that the SVT unit is a good upgrade
) in high demand conditions.
Also something could be said for the fact the coolant stays in the engine for a shorter time without the restriction of the thermostat and may not soak up as much heat as it could. Therefore "possibly" losing some efficiency and giving a cooler reading then otherwise. (I.E. less heat being drawn out = cooler reading coolant temps, yet hotter actual engine temps)
Then there are the obvious problems of running in mild or cold weather where the engine will not remain or even get to proper operating temperatures.
