tabby is right an amp would work better but that will come later, any mid to lower mid priced speakers would work well and the ratings mean little, kenwood, poineer, lower end mb quarts. alpine speakers are good.
the problem is people usually get a new set installed and right away turn up the volume until the deck runs out of power and it is likely the limits will be reached about the same time as the old speakers resulting in distortion.
you may get better sound quality until you turn it up too much the deck will run out of power before the speakers are overpowered.
make sure you do not have a factory amp in the car before you start
