Coolant for the PT Cruiser
 

Is it really very important that you use "the right" coolant? Isn't Prestone antifreeze and water good enough?

Yes each different coolant has a different chemical makeup for the type of metals in the system. Using a universal will get you by but not make your system last or work as designed. Will take a BMW for instance. The type of coolant needed has a lubricating property that allows the electric water pumps to work and not rust up.
Chrysler stuff uses HOAT is most case which is designed not to rust and corrode the type of aluminum in the block and water pumps..
GM used dexcool because they cant seal up there cooling system always has leaks there is an additive in there that self seals there blocks intakes and so on..
So yes having the correct stuff in there is to your advantage.