It's really not necessary for any climate in the U.S. to stray away from the factory coolant. I run the factory coolant in the off season. So no need for additives, the engine simply isn't going to get hot enough to cause damage.Any opinion on Mishimoto Liquid Chill for general use? It’s advertised to mix with any coolant and one bottle for our (FL5) engines. I’ve used Water Weter too and had zero problems, but only minimal cooling.