You can run the speakers from the deck yes, but to get some reasonable sq, you really do need an external amp like Jani said.

here are some midbass speakers for refrence
http://www.sonicelectronix.com/cat_i...s-drivers.html
...i've never ordered from that site, but i like to use it to look at and compare different audio components so i know what i want to listen to when i go to the shops.

if an external amp is an option for your fronts and rears, my .02 personally likes the Alpine MRP-F250