Subaru factory subwoofer kits - differences?

[Black88GTA]

I'm looking into getting one of the subaru factory sub kits to mount under the passenger seat. I'd kind of like one of the 120w versions, since I'd like the extra punch over the 80w (p/n H6300AS030).

A few questions though. What's the difference between the various part numbers? I'm seeing:

H6300SS601
H6300SS202
H6300SS600
H6300SS601
H6300SS800
H6300LS300

and I'm sure there are others I'm missing. These are all 120w units - I'm assuming the only differences are mounting brackets and maybe wiring? Does anyone know which one of these includes a bracket that is most "adaptable" to the SVX? Do the 80w versions have the same dimensions as the 120w? I saw in another thread that someone fit an 80w version - I want to make sure that the 120w will fit as well before I buy one.

Does anyone know?