I installed a 180deg. thermostat in my S last spring as coolant temps were rising more and more with each passing day. Upon draining the coolant, I noticed lots of air had somehow been trapped in the cooling system...from the JCW install I assume. I installed the cooler thermostat anyway and the temps during track events and daily drives were always low.

We all know that the past two winters were very mild. This winter, temps in NY have ranged from -15 to 20 deg F for about 5 weeks. fuel mileage has gone waaay down as has power output at WOT - and there is no throttle yip-in response, all or nothing. I re-installed a new stock thermostat. After ~250 miles of driving the engine light went off, mileage is up about 3-4mpg, tip-in throttle repsonse and WOT is much better, and, the car gets nice and cozy.

These oil/coolant temp observations were made via the Chrono package guages.

Just an FYI.