I am trying to educate myself more about the audio system in the '05 STi before I jump in and start upgrading. I have some questions though as I am very unfamiliar with the 'lingo.' Is the STi '2-way,' 3-way,' 'componant'?...these are all terms that get thrown around that I am unfamiliar with.

Most stock speakers are single drivers, as in they have one driver (tweeter, mid-woofer, woofer) per speaker.

Take a look on crutchfield and look at the differences between them. The STi has the equivalent of a component set, where the frequencies are divided between a woofer and a tweeter.

A true component set will have a crossover, which splits the signal and directs the proper frequencies to the correct driver. It wouldn't make sense for a tweeter, which has a very high frequency response (above 3000 hertz), to receive a signal that includes bass frequencies (less than 500 hertz).

A two way speaker will have a woofer and a tweeter combined, with an internal crossover to divide the signal. Three ways will have a woofer, a tweeter and either a mid-woofer or a super-tweeter. The latter usually is a waste as the upper limit of human hearing is about 20,000 hertz (or 20kHz) and some speakers are rated up to 22kHz.

There are many options for you to choose from, it would be beneficial to search the forum and see what others have done.

When you decide on what you'd like to do, do it once and do it right. Don't skimp on install materials or procedures. The most important thing is to remember that sound is highly subjective, so make sure it sounds good to you.