Well, the temps are held pretty close... A thermostat 'regulates' within 10-20 degrees F. The ones now-a-days are pretty fast acting, no 'float' to close, then open.

And, with weight savings, radiators and pumps are held pretty close to optimal also. There isn't much reserve there anymore.

 

Here in norway we have really high taxes on cars so a A6 1.8T Avant costed in 2000 $85.000, while a 2.7T costed $120.000. RS6 costed $280.000 . The bigger the engine, the higher weight etc. The higher the tax get. So to be able to sell any cars they have to sell them with small engines also.. The most sold A6 in Norway is the 2.4 and the 1.8T. Theres also many 1.9TDI.

 

m00035 most thermostats pass some water when closed as a safety feature - very few cut it off completely.