Factory systems provide an integrated look too, with lighting and controls matching the rest of the dashboard. Knobs and dials are often bigger and easier to use, and many systems come with controls on the steering wheel. And they can be covered by your new-car warranty, which can make service easier if problems happen.

But expect to pay a high price for a high-end factory system. And many don’t allow you to easily upgrade with new features or technology, or to replace the radio with a more up-to-date one.

Almost always, you will get more features for your buck with an aftermarket system, and you may be able to equip your car with premium features that just weren’t available for the model you bought.

Aftermarket buying requires more effort to shop for the right system. You can take the time to find the individual components yourself and then take them to an installer, or talk with an installer for a complete system.

Before you buy, check your cars warranty to be sure that nothing you’re planning to do will void it.

For most people, the automaker radio that comes with your car will probably be fine. If you’re looking for the best audio quality or more features, compare what you get with an automaker’s optional premium system and what you can get with an aftermarket system. If they’re the same and the factory system isn’t that much more expensive, that’s probably the best way, given that it will save you installation problems, will probably be better fit for your vehicle, and will cost less in relation to the total price of the car.

But you might find that you will get a better system for the same or less money by going aftermarket.

Do you want Satellite or HD Radio? If you want great audio quality but don’t want to have a monthly subscription fee, you might want to try HD Radio. The digital signal makes AM sound closer to FM and FM sound more like a CD. You can also explore the diverse sub channels that radio stations are broadcasting. But you may want to wait before investing in HD-Radio equipment, especially as more and cheaper gear arrives and more stations add HD Radio capability.

Anyway, if you want a much better selection of music, news, sports, and other music than you can get through local stations, satellite radio is the way to go. It’s appealing if you travel out of your region a lot and don’t want to be limited to the local radio. Sirius and XM provide musical choices that are similar, but if you like sports or celebrity DJs, check out their channel choices closely before you sign up.

If you want to choose your music for the road but don’t want to carry around a lot of CDs, look for a system that has a USB port, hard drive, or iPod/MP3-player included. With a hard drive, you don’t have to worry about lugging around and plugging in a different device, and it can store and let you sort quickly through lots of data, whether audio or picture files. But the media stays with the car; you cannot take it with you unless you download it to another device. In addition, if you already have an MP3 player or iPod, adding a hard-drive music collection and setting up new playlists could take lots of time to load.

A device that lets you plug in an iPod or MP3 player would be a good choice if you already carry your player with you most of the time and don’t feel the need to recopy your music collection. If you buy a device or aftermarket adapter with a dock, you can charge the unit while you drive. And some aftermarket systems let you handle the device with radio/and or steering -wheel-mounted controls.

You can also make an existing system accept an iPod, but this would not have a good appearance.

The top companies you’ll want to look for if you want to upgrade your car subwoofer are JL Audio, MTX Audio, and Kicker. These three are leading the car audio industry, all with early origins. JL Audio’s W7 line is one of the most advanced and most powerful subwoofer lines available on the market (pricey, but well worth it if you care about the quality). MTX Audio has released an amazing 60-inch subwoofer that holds the record for the size. They also have the largest consumer subwoofer that measures at 22 inches. Kicker’s L7 seems to be the best from the Kicker lineup, and there’s no reason why it shouldn’t be.

Cars usually carry their subwoofers in the trunk or back parts of the vehicle because of the lack of space. Subwoofers and their enclosures tend to take up more space than is expected. As such, fitting them into dashboards and doors is extremely difficult.

An interesting thing subwoofers are used for are volume competition, also known as SPL wars. SPL (sound pressure levels) get extremely high in these battles, and some companies decide to produce subwoofers geared extremely towards the SPL rather than the sound quality. Companies like JL Audio have focused on both SPL and sound quality, as shown in JL Audio’s W7 series.

When installing a car stereo subwoofer, it sometimes requires modifications to the vehicle itself. Obviously, each car is built differently, and that includes the space allowed for upgrades/changes like the subwoofer. If you want to shoot for a larger one or one with a different shape (although mostly circular, some subwoofers are square), it’s important to make sure you have the right size available; otherwise, its time to bust out tools to make it so that you have the right size.

Never assume that a smaller subwoofer is weaker. For example, JL Audio’s 8-inch W7 subwoofer is more powerful than some 12-inch subwoofers from other companies. Because of this, you must always read reviews on the subwoofer you’re looking at before buying it in case that smaller subwoofer is indeed weaker. If you keep with the more popular brands, though, you shouldn’t have many problems, because these have been reviewed many times over and won’t fail to deliver.

Car stereo subwoofers sound like enthusiast-only business, but they dig deeper than most people think.