Subwoofer size

[Yanayaya]

I've found loads of information regarding speakers and stereos in the Monaro, removal, upgrading etc etc. What I can't seem to find is the subwoofer size of the standard subs and their possible replacement options. Does anyone know off the top of their head?

[Yanayaya]

Instead of subs you could install some very nice speakers in there instead for even more sound. It depends how that would all balance out.