I think that it’s implicit that the volume of Godzilla would increase; we need to assume that the bounding layer has a degree of elasticity and that that the matter displaced by the flotation cavity will expand into that, reducing the net density.
Mighty Godzilla, with power untold
Rises through the waves; his powers unfold
Hidden muscles in clever design
Create a new chamber as they realign
Inflating his body, a titanic display
Defying the depths, he floats up and away
No long bound by the oceans’s might
Godzilla soars, a triumphant sight!
It was the Honda FRV and I still have one. I also had a Multipla. Both are good, in their own quirky ways. Both have slightly narrower seats than a normal car; the honda slightly narrower, but more supportive, have heating and are leather. Both are very car-like to drive, but the Honda has way better engines and better reliability. That said, getting parts for the FRV is a pain, because there weren’t many made and the wider body means that a surprising number aren’t shared with other Honda models if the same era.
Given a choice, as a practical family car, I’d take the FRV over the multipla. I do have a soft spot for the multiplugly though.