The head unit in your vehicle is the source of your car's sound. The type of media that can be heard through your speakers depends on your head unit.

Reasons for upgrading your car's head unit are numerous.

If your head unit can play eight tracks, it would probably be wise to upgrade.

More power, clearer signal, more features, and looks are just a few of the reasons for upgrading your head unit.

Head units have the most variations compared to other components of stereo systems.

CD, Minidisc, Cassette, and DVD are all different ways that you can get sounds and even images into car.

However, there are also different formats that can be held on CD. For example, some head units are able to read compressed audio such as MP3's and WMA. Head units equipped with this will cost more than those that are unable to read these formats, however, you will be able to put way more songs onto one CD, as many as two hundred!!

The head unit that you require depends on what you plan on doing with your car's sound system and what features you need.

I would definitely suggest purchasing a head unit equipped with MP3/WMA decoding if you are able to burn many songs onto CD's. Because you can hold an extreme amount of music on one CD, you do not need to change CD's, and do not require a CD changer.

As for power, most head units have more than enough to push your stock speakers, however, if you plan on upgrading your speakers, the internal amp may not have enough power. Some higher end head units are not equipped with internal amplifiers and require external ones. If you are willing to put out the extra cash to purchase one of these units you may do so, although personally I would just stick to one that is equipped internally.

There are hundreds of companies that manufature head units, and of course some are better than others, and you will have to pay more for these. As with most things, you get what you pay for. If you dish out more money, you'll get a better head unit...most of the time.

Some of my favorite brands of head units are Alpine, Rockford Fosgate, Pioneer, Kenwood, and Blaupunkt.

I would suggest looking around at what head units are available on the market using the web and various sites such as Sounddomain.com and Crutchfield. If you go into the store with the knowledge of what is available, it will make the shopping experience much easier.

Also, be SURE to LISTEN to the head units that you are interested in through the same speakers, or speakers that you are looking at upgrading to. I cannot tell you what head unit to purchase, as everyone's personal tastes are different and hear differently.