I recently got a pair MTX terminator subs that have 400 watt RMS what kind of amp should i get?

i think the woofers are 200 watts each so how much RMS do i need for my amp and how many channels? will it sound ok if i just power my subs or is it better if i power my car speakers and the sub? and if it is better for me to power all the speakers, what kind of amp should i get?