How do I add another set of speakers to my car?

If i add new speakers to my car do i need more power?

• So i have a saab 9-3 01' and the speakers are horribly distorted and are blown to the max. I want to add new speakers to car without messing with power because the computer and dash and speakers are linked to the same power supply, so if i alter it it might mess up the car. So i was just wondering if it is possible to add speakers without increasing the power to them? Like simply buying the same size speakers and putting them in; would that present a problem? Thanks so much any comments are appreciated. (im a noob)

• Answer:

  you have to buy speakers designed for a stock radio, like the alpine S series. i recommend speakers with less than 50w RMS rating.