Speakers
Speakers are usually classified as full range, tweeter, midrange, woofer, or sub-woofer. A full range speaker is designed to handle the full range of sounds most people can hear.
Full-range speakers
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 fuss. They come in a variety of sizes that mount easily into factory speaker locations.
Component speakers
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.
Most component car speakers cost more than full range speakers of similar quality
How to Judge a quality speaker system
Sensitivity
This measures how much sound a speaker yields from the power applied to it. If you have a low-powered car stereo, like most factory systems, speakers with high sensitivity ratings will make the best match. If you have a high-power system, like that provided by a brand-name receiver or external amplifier, then consider speakers with lower sensitivity ratings. Properly powered, they’ll provide excellent sound quality. As a general practice, any speaker system having a sensitivity rating of 87dB and above is considered capable of delivering good quality sound. Power-handling
This lets you know how much power(measured in watts) a speaker can handle. If you’ve got a low-powered system, your speakers don’t need to be able to handle lots of power. On the other hand, a system with powerful external amps will require speakers whose power-handling is close to the output of the amps. And remember, the key spec in power-handling is the RMS power-handling, not the peak power handling. RMS ratings realistically measure how much power the speaker can handle on a continuous basis, not just for a short period of time
The materials used in the construction of the woofer, tweeter and surround is very important for sound quality and determines the effectiveness of the centerstage in an environment. If you are a music enthusiast and would like to hear sound and not noise, I would suggest you go in for the component speakers and couple that with an equally powerful AMP and a sub. A cost efficient proposal would be the Alpine components - Use the SPR17LS components for the rear and SPS front speakers along with The Alpine MRV F450 5-channel AMP to power the entire unit - the headunit is also an important component and a general rule to follow would be to use the entire set of speakers and head-unit along with the AMP to be of the same make and model(same manufacturer)