Stereo System

Just about all cars come with a stereo system, unless it has been taken out. There are multiple components to the stereo system, and things you can add to your stereo system to get even better quality. The possibilities are endless and can be costly, but it's all worth it.
Head Unit. This is the part of the radio that you think of when you are thinking about a car radio. It is where you put your CD's in or change the radio station. Behind this there is a harness of wires that go all over the place. Some to the power, some to the antennae and then for the speakers of course, and others else where that doesn't really need to be covered.
Types of speakers. You have Tweeters, Mid Ranges, and Subwoofers. Tweeters and midranges are stock in just about every car, subwoofers are usually aftermarket installed, but the mid ranges will support a small amount of bass. Tweeters are all about the high pitched noises. Sound is measured in Hz, and tweeters cover the higher numbered Hz. They are usually small and not very noticeable, unless of course you install larger ones. Mid Ranges are what you think of when you think about the speakers in your car. These are the speakers in the doors and panels next to back seats. These speakers are a combination of a subwoofer and a tweeter. They give you middle level range hz which some bass can be heard from alone with treble (vocals). Then lastly Subwoofers. These are usually a lot larger than your mid ranges and most cars do not come with just a subwoofer to increase the bass. They are installed by the owner or the owner has them installed by a professional. And when having them installed, because they require so much power, you have to wire it through the car battery and through an amplifier.

Exhaust systems

The exhaust system is a series of piping that is used to guide exhaust gases from the engine away from the engine. The system moves burnt gases from the engine through either one or more exhaust pipes. The first part of the exhaust system is the header manifold. It is designed to collect the gasses that come from the cylinders into one set of pipping. The factory made ones are made out of cast iron, but aftermarket ones that you can purchase and install are sometimes made out of other materials. The manifold is purely a performance piece. Getting an aftermarket manifold and increase the performance of your car. It does this by allowing easier flow for the exhaust allowing more to be pushed out. Next would be a catalytic converter, but some systems take this out which is illegal in some places. Lastly we have the tailpipe. This is the part that most people think of when they hear exhaust, because this is the only part you can easily see. This is where the gasses exit the exhaust system. They go through the muffler which is supposed to make the exhaust quiet and exit the system all together. Some car enthusiasts will change the muffler to allow more airflow, or to even make the exhaust louder. The exhaust can only legally be a little louder than factory.