Great news! Now if you don't see any reduction in the amount of coolant in the resovoir each morning, checked when the engine is cold, it's just your temp needle placement... you can quit worrying altogether.
Clusters go out on boxsters all the time and needles are replaced rather poorly, even at dealerships. Who knows if yours has been replaced or not if you are not the first owner of the car.
BTW, when (or if) you swap your gauge faces out for white or silver ones, you can correct the potential needle placement variation.
