DO NOT HOOK THEM UP IN PARALLEL. Like Jon said will fuck your amp up unless it .5 ohm stable. As far as wiring the subs go here
http://www.crutchfieldadvisor.com/learningcenter/car/subwoofers_wiring.html?subs=4&impedance=DVC4x2, it will either be 2 ohm or 8 ohm, unless you run 2 per amp. As far as the mids and hi's. Its better to have more power than not enough. If you have too little power when you turn the volume up it will destort alot more then if you have more power. Just remember distortion KILLS lol. Also you want to run the rca patch cords from the radio to the eq and then to the amp. If you need anything else hit me up.