I have a 10" in my Integra sedan. Although I have it in a custom ported enclosure, and it will very easily shake my rear view mirrors with only ~300 watts feeding it.

For me, sometimes its perfect, sometimes I want more bass.

For you, I would suggest a 10" because the size difference and cost should be minimal. And powered enclosures usually are designed to save space and not maximize the woofers capabilities. Again, this is VERY subjective.