The cooler thermostat makes some sense but here is my question: A thermostat really controls the engine'* minimum operating temperature. Air flow directed by the fan controls it'* maximum temperature. My point is that a lower temp thermostat shouldn't prevent overheating, the ability of the cooling system to disperse heat does. So unless you are replacing the thermo switch that controls the fan so that it kicks in earlier, or increasing the capacity or efficiency of the cooling system, a thermostat shouldn't prevent an engine from overheating. However, if the stock 195 degrees is too hot, that is a different story. Does this make sense to anyone?

You're right, but the 180 prevents that intitial 'heat saturation'. My car'* average operating temp dropped about 10° with the drilled 180, and no other mods done at the same time.

There are fan mods you can do, too, but my car is running where I want it temp wise now, so I'm not planning anything else.

With the 180 undrilled how much a difference will that make especially on a 2000+ ssei?

It seems the arguements FOR the 180 are much more strong on the older ones(99 and before) with the plastic intakes or the NA'* in general.

True...granted there many be a SLIGHT loss in MPG, but the trade off is worth it

The theory of the lower temp t-stat is to start the cooling process sooner allowing the cooling system to do its job. Going too cold on the t-stat (160 etc..) without major mods to heat the engine up will cause the engine to come up to operating temp much slower resuling in reduced fuel efficiency and a long time for the heater to warm up in the winter. A lot of people run 160'* in the summer and change out to 180s in the winter...

Only the ones who have HEAVY mods have a 160, some members in the northern climes have even resorted to removing their 180'* and re-installing the 195. Upon return of sub-arctic temps, the 180 goes back in