Some people seem to think that the Boxster cruises at 180 degrees because the temp gauge needle typically sits between the "8" and "0" of the "180" label when at cruise. I don't think that Porsche labeled the gauge so that 180 degrees is indicated when the needle is in that positiion...even if they might have made it deliberately misleading. The temp gauge has a blue-tinged tic in the vicinity of the "100" label, then an unlabeled tic, then a tic above the left side of the "8" in the "180", then another unlabeled tic, and finally a red tic in the vicinity of the "250" label. That being the case, the common temp gauge needle position at cruise (between the 8 and the 0) might be inferred as 200 or maybe more. I suppose that the unlabeled tic to the right of 180 could be inferred as 225...
The Boxster engine actually runs above 200 degrees at cruise, but (in stock form) has a 180 degree thermostat. This is possible because the Boxster's thermostat is on the INLET side of the cooling system. This is made clear by the cooling system diagram on page 19-2 of the Bentley service manual. So if the coolant returning from the radiators has to exceed 180 degrees to begin opening the thermostat, then the coolant leaving the engine (headed for the inlets of the radiators) must be significantly hotter than 180 degrees...and that's why an engine with a 180 degree thermostat actually runs in excess of 200 degrees at the temperature sensor location. This also explains why the 160 degree thermostat can result in cruise temps in the 170s - 180s.
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