I'd suggest thermocol and packaging foam. Paper can't stand up to the handling of the courier people unless its thick (many sheets). If you don't mind spending then a wooden crate.
absolutely not, the box will be thrown around, no matter how heavy it is, so make sure you pack it with more than paper around the sub, else be ready for some proper damage
Edit: something useful
have proper foam around the sub then thermocol all around then the box for it reach safely, also the external box needs to be bigger and the walls need to be thicker
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Use thermocol, etc. on all sides. The fitting should not be either loose or even too tight.
You are in a metro city. See if you can find some courier company to pack and ship.