If you're planning to upgrade your factory stereo, an amplifier plays a critical role in the quality of your system. It acts as the power source for all of your speakers, so making sure you select the right amplifier for your budget and needs is critical. Amplifiers take the power from your vehicles battery and engine and amplify it so that it can support the power required by your speakers. Depending on the size and power required by your speakers, you want to make sure you're getting the amplifier that durable and can support your systems needs.