What type of speakers do you need?
Aftermarket car speakers can be divided into two main categories: full-range speakers, and component speaker systems. Let's explain each and look at their advantages and disadvantages.
Full-range speakers contain all the speaker elements in one basket. In their simplest form they consist of a woofer for the lows, and a tweeter mounted onto the woofer to produce the highs. Some models will have additional drivers, like midrange or supertweeter. You should choose full-range speakers if you're looking to replace factory speakers with a minimum of muss and fuss. They come in a variety of sizes that mount easily into factory speaker locations. In most cases, you simply remove the old speaker, connect the new speaker with a free Crutchfield wiring harness, and mount it. You'll find full-range speakers at nearly every price point and power range.
Component systems use a superior speaker design to give you the best possible sound. A typical component system includes separate woofers, tweeters, and external crossovers — all of which come designed to work in concert with one other.
In a component system, the tweeter comes separate from the woofer, and you can mount it in a location that provides the best imaging. Your music will sound more realistic, more "live," and have greater depth. The crossover network in a component system comes external to the woofer and tweeter, so higher quality internal components can be used to ensure a sharp delineation between the frequencies sent to the different drivers — that means more realistic sound for the listener. Component systems are generally made of better materials than their full-range counterparts, so they're capable of delivering exceptional dynamics and detailed sound.