Engine thermostats don't keep the engine cold - they keep it hot.
A proper cooling system has enough radiator and water flow to make the engine -too- cool, and then a t-stat to restrict the flow to keep the engine *up to* proper operating temp. I.e., if you were to run with no thermostat (constant full flow), the engine would never get warmed up.
Running a 160 t-stat is generally a bad idea. I wouldn't run less than 180. One reason is, that when the engine cools, condensation builds up inside and drips down into the oil. When you run the engine next time, you want it to get hot enough to evaporate that bit of water out of the oil. Otherwise, it builds up over time and water in the oil is a sure-fire recipe for a ruined engine.
If your cooling system itself is not adequate to cool the engine, then a 160 t-stat doesn't do jack - because at any temp of 160 and above it's just wide open all the time anyway.
If the cooling system IS adequate, then you don't want to hold the engine at such a low temp - better to bring it up to 180.