Hondatuner, just install the blue, which is what I have, and in hot weather, you might see the eco light every once in a while, which is no issue at all.
Niels, don't worry about it, as all it is a wire and an inline resistor.
Tick, you have other issues not directly Muzzler related.
Regarding overheating, if you start to see the temp gauge rise past where it normally is, with or without the Muzzler, you need to take a look. Remember, at least in my case, the temp gauge was basically in the middle pre-Muzzler, and just slightly below the middle, post-Muzzler. You'll know when your car is starting to overheat. You'll see it, and you'll smell it!