I've got one 10' inch sub powered by a 2oo watt amp. i have yet to get a box for it.
i dont care much for bass, a little thump is good enuff for me
I did however replacee front and rears with rockford 5 1/4 speakers and tweeters. I ampedd em with a kenwood 320W 4 channel amp. I have yet todo the install cuz i need a deck but I think a 10' is more more than enuff, if you dont like a lotta base
I hear alotta guys who do 2, 12's but keep the stock speakers and all you hear is base when ur riding and no sound