Shocks handle bumps, springs handle weight. Tires, you have to look into that, but yes, they make tires that are better for towing. Yes, you can uograde the cooling system and trans cooling.
Its not the towing, its the stopping that is hard to change so if you get in an accident, your insurance won't cover it if you were towing more than the manufacturer says is allowed. I am not sure what your vehicle is limited to though so just make sure you stay within the limits and you are good.