How far you go depends on how sensitive you are to rattles?
Doors are worth doing, make sure you get some on the outer skin and the inner frame work. Worth putting some on the plastic door cards too. Doors will be dead after this.
In the boot there's the obvious floor and bulkhead to cover up but I can imagine the plastic parcel shelf would get quite rattily with the sub going for it so maybe get some on the backside of that too. The knock test is your friend when installing vibration damping material, if it sounds tinny or rattles when you knock on it with your knuckle then a sub will make it sing.
The boot lid is single skin in some places and will probably need some going over. As far as I could see, the rest of the car is quite well insulated already with nice thick carpet and foam. Only places I can think of that might vibrate are the rear arches which are single skin, problem is you would have to remove them to dynomat them so probably not an issue unless you're going for professional audio.
