Like hyperv6 stated: modern engines are designed to run "hot" - "hot" being a relative descriptor. You cannot make the cooling system more efficient by adding fluids that give up heat faster than a 50/50 mix of water and DexCool.
Ecotec engines will not run cooler than 180 degrees unless the thermostat is removed or stuck open and the ambient temperature is below 40 degrees or so. Then, the ECM will disable the ac compressor, disable the temperature gauge and DIC reading, and the engine will be running in an open loop mode, which is highly inefficient and wasteful.

 

I used WaterWetter in an SHO I had and I saw no difference in running temps. The only thing I got was a lighter wallet.