To run a 180 T Stat you will need a Diablo tuner to adjust the fan settings to come on at a lower temp. If you do not do this the engine will still run at the high temp although it will take longer to reach it.
I thought I read somewhere that you will also throw a check engine code for the engine not coming up to temp, and it would run on a "cold engine" setting, waiting to get up to temperature.
As a side note, I had this code last year and my temp gauge was at the 3/8 mark when it came in. Dealer put in a new thermostat and it runs at the 1/2 mark all the time now. I have no idea what the range on the factory gauge is, so.....
