I have 180, and would go no lower, one because of what GT black said, or as i call it, "warm up mode" I don't know of any programmers that will set the temp lower other than just changing fan temp. The other is my car is my daily driver and in ohio i need a hot heater in the winter. stock about burnt my leg hair off and the 180 is hot but not scalding, I heard a couple complains of people who have 160* in cold weather and complained that it just never got warm.