high water temp?

[Cloudsurfer]

I am with you on the lower temp T-stat- once it is open, it is open and the system will regulate itself based on the cooling capacity of the radiators. Now, opening sooner will give the system more time until it reaches this point of equilibrium, but still, assuming the car is to be driven for more than 20 min it becomes a moot point.

If you want to wind up with cooler operating temps you would need to add cooing capacity- either with larger radiators and thus more coolant volume, or by taking the oil cooling out of the liquid cooling loop (by eliminating the laminar flow oil cooler and installing a conventional air/oil cooler) or some combination of both.

The coolant Porsche fills is absolutely not lifetime fill, and you certainly cannot do any harm by changing it- provided that you do it correctly (when bleeding mainly).