Alpine type s

I just got rid of my orion 12'' speakers and am in the market for 2 of these alpine type s. what wattage of amp should i get. should i get an amp thats similar to my subs rms or peak? what dos the dual 4-ohm exactly mean? and finally should i get an amp that has 2-ohm or 4-ohm?
dose hooking up two subs to an amp change the ohm or wattage?
i dont know a whole lot about this stuff heh

frequency response 26-1,000 Hz
power range 50-300 watts RMS (150 watts per coil)
peak power handling 900 watts
dual 4-ohm impedance

Thanx.
Charmm

if you want to use a class D amp you should get dual 2 ohm subs.. when you wire them together you'll get a 2 ohm load and the find an amp that runs between 400-600rms @ 2 ohm if you want to use a 2 channel amp buy dual 4 ohm subs.. then you can find an amp that does 200-300 x 2 @ 2 ohm

and these subs are great.. but i went up a level n got the type R