I'm not worried, I think it is all a very useful discussion sort of related to the topic. My personal thought is it helps evaporate the fuel better so it burns faster and more completely before the ex valve opens and relieves the pressure, anything burning after the ex valve open is not contributing to power or MPG. Secondly a higher temp evaporates out sludge forming moisture in the oil faster so it should help longevity, probably more of an issue on engines that get driven a lot of short trips and don't see max temp much. Also just having a thermostat in the system makes tuning easier as it holds at one certain operating temp instead of continually fluctuating based on load and outside temp and such. My heater feels a little hotter with a 205 stat and it gets cold a lot here. All things considered it is not a huge deal but they are cheap and easy to swap so a fun thing to play with.