Galactic-Don't worry about the heat; your Nissan parts didn't fail because Fla is so hot-that is just the BS the Nissan folks will tell you to explain why their POS failed so early.There are much hotter places in the USA than FLA-(maybe not as humid, of course, but electronics don't sweat, so just the heat matters).
Any decent modern vehicle will be able to take what south Fla has to dish out.
Now, AC's will be used more in hot climates, so they will wear out sooner(year wise), but not much you can do about that but use your AC less if it is a big concern.
Don't worry about it. The engineers who design these vehicles are aware that the USA has some warm areas.Luck,Charlie