how many subs does it take...

[rpster]

...to rock the yaris like the commercial?

just kidding, although i do have a few questions...

im working on installing some thump into my hatchback, but im having the hardest time deciding between two 10s or just one. i have one pioneer slim 10" on the way, but was curious if having that second sub would be worth it.

i also got the gm-5300t amp; although, at the time, i figured id only run one sub. would it be advisable to run two? the subs rate 250w rms, and the amp rates 380w rms bridged or 2x125w rms. should i get a beefier amp if ill be running two 10s?

ill also be making my own enclosure thats just over 4.5" thin to have pretty much the same dimensions as the floor of the boot and have it attached to the spare tire cover/floor.
i figured i wanted to retain as much usability of the entire car, including my boot.