[AznRolla]

I would recommend going with one good sub, that way you still half your trunk to load stuff in.

With the size of sub you want, it depends on what kind of music you listen too... if you just want booming bass, the bigger subs are better. If you want tight bass such as in rock music, go with a 10" sub.

Also, larger subs tend to play lower frequencies better... i.e. 20-75 hurtz range. If you listen to rap, than the 12 will be good.

You also need to determine what kind of box you want. A sealed box will give you punchier bass than a bandpass box will. Bandpass will sound louder, but it will also be more of a sloppy bass.