It depends on how serious you are planning on getting into coyote hunting. If you aren't that serious, just be a fair weather caller and go when the conditions/wind speeds are right.
I have the Fury and an external speaker. I hardly ever use the external speaker unless I am in a coyote tournament and need to really fight the wind. It is more of a pain in the ass to carry around. If you want to spend the cash and upgrade, you could get the CS-24... it isn't very big and has good volume.
I will say, the average coyote hunter with the ability to go louder with the call, probably scares/educates more coyotes and ends up shooting less than if a person had less volume.
If you have wide open spaces with good visibility, volume is your friend. If you are hunting where they can sneak in or follow low spots and get close, you will blow more coyotes out because it is too loud and not natural. Good Luck, hope this helps.