Simple high school Fizix:
The hotter an internal combustion engine runs, the more efficiently it operates. Do not mistake efficiency for power here. And DemonSVT is correct- simply running a cooler thermostat in these cars with the computer controlled fans and whatnot will just cause delay of the fans operating to get the car back up to specs, and so to get it to run cooler you are looking at monkeying with a little more than just a thermostat. Unless your car has cooling problems, I would not defer from stock specs on this, but then again, this is your car and you can decide to do as you wish with it, but running the engine cooler IMO just wears down the engine faster. Just my 2 cents worth.
