I'm asking this question again because i only got 2 answers and non answered the question.
I'm a noob when it comes to car audio system. I want to install a full aftermarket car audio system in my car and i'm trying to learn as much as i can. So far all i know is...

1. Head unit (of course)
2. Speakers
3. Subwoofers
4. Tweeters
5. Crossover
6. Amplifier

What else am i missing?

I want it to be loud but nothing outrageous. Like head turning loud but not necessarily jaw dropping (you get the idea). But most of all the best sound quality. I'm going with component speakers rather than coaxial.

So just a rundown of the components that make up the most awesome sounding audio system would be much much appreciated.

p.s consider $$ in not a concern.