Just to let you know, I had the 160 thermostat in my 2000 4.7L Durango. It did throw a code: 1281-"The engine is staying cold too long-check your thermostat". It did not show the check engine light at all. I only found this out when doing the ignition on-off, on-off, on and looked at the odometer reading. That is when I found the 1281 code. The 160 did make my engine run very cold--even in high summer heat. My AC did seem colder though, but I couldn't be 100% sure.
Anyway, I went to a 180 Degree Thermostat, cut in the notch which you need to do for the rubber gasket to fit properly, and even drilled the bleeder hole to match the stock tstat. I went as far to make sure the hole and notch were in the same place as stock. I haven't had any problems since. I will say it runs colder than the 195, but no way near as cold as the 160. As for not enough heat in the winter, I didn't see any problem there. It still got plenty hot to keep you warm on a 20 degree day.
Intake Air Temperature sensor. Tells the computer the air temperature coming into the intake manifold. Do a search in the forums. Alot of info on that. Rockadacous has an excellent write-up. It is moved from the stock location on the intake manifold, which is unnaturally hot due to engine heat, to an upstream location closer to the air cleaner, where the incoming air is more at the normal ambient temperature. Typically, the hotter the computer thinks the input air, the leaner is make the fuel charge, hence less power, comparably. Placing the IAT in a location where it senses the real temperature tells the computer to richen up the fuel charge, thus more power. It is widely thought that the manufacturer places the sensor in a warmer than natural location to achieve a bit better fuel economy.
Some folks think moving the IAT such as 'tricking' the computer. Actually, the technique can be considered untricking the computer from stock.
ALRIGHT!! I finally scored a 180 t-stat, but it's a Gates brand, forgot the part number, but does anyone out there have any feedback, good or bad, on this particular t-stat? I gave up trying to get the Shaw or Stant part. State motto in Maine ... The way life should be..unless you need a specific auto part, then you're screwed!!