So you want to upgrade your current car stereo to a phat sound machine with specialty or aftermarket parts? Beyond your personal tastes and desires for items like a head unit, speakers, and woofers, you should probably be aware that you'll need to upgrade your battery and alternator; most production vehicles' electrical systems are not designed to run high-power aftermarket audio equipment. In fact, most vehicles' electrical power range lies between 600 and 1,200 watts--not much for a big, loud, fancy car stereo.
Once you've decided what exact pieces you want to install as your car stereo system, you can then see how much more power you need to run them and begin to get yourself the necessary high-powered battery and alternator. But you'll also need to upgrade three very important wires under your hood referred to in this video as "The Big 3." See how it's done:
"The Big 3" wires are the positive charge wire from alternator to battery, the engine ground, and the battery negative that runs from the battery to the chassis. And here in this video we get a practical demonstration of how it's done and why it's important for the operation of your big pimpin' car stereo. You can opt to add on to the existing factory wires or replace them outright with zero gauge wire. And all of this wire tweaking leads up to the installation of a Kinetic HC1800 car battery built especially to run high-powered car audio.