[thstone]

The higher temp thermostat on a street car is also related to oil change duration.

Running a low temp thermostat may not allow the engine to heat up (depending on the weather and your driving) enough to burn off the moisture in the oil on a regular basis. Running the 186 deg thermostat tries to make sure that the engine gets to full temp more readily and thus allows Porsche (and almost all other car makers) to extend oil changes to more than 10,000 miles.