I installed the LN low temp thermostat a few weeks ago. I noticed that the temp gauge seem to sit at the lower temperature for a while but then eventually moves back up to its previous normal temperature position (needle approx vertical on a 1999 986). I figured this was because once the thermostat is wide open the final running temperature will be dependent on the radiator design/size etc.
One word of warning though. If you do a coolant flush don't park your car on an inclined driveway with the back end point down the hill. The air vent for the system is at the rear but the radiator is at the front. I had an air bubble in my radiator, went auto-crossing and blew my boiled coolant all over the place. For those of you without PhDs in physics; air goes up.
