go to crutchfield.com n click on "outfit my car", then u will put the makr n model n year of ur car, then it asks if u have factory stereo or a aftermarket one n some other stuff blah blah... but when u finish, it will give u the size of ur speakers n they give a u a list of all kinds n...
if this is ur first system then i guess it will be alright but eventually ur gonna want more n more bass... i did the same thing n bought a complete system for like $300 n they were 2 12s.. n they hit hard but now im looking for some more powerful ones like the jl audio 12w7... i would always go...
its rockford fosgate so get a powerful amp haha... wut i would do is get an amp that is a LIL HIGHER than the total RMS of BOTH speakers, (always go by the RMS power n NOT the "peak power") and i would just start the gain setting at low n slowly turn the gain higher n higher til my speakers...