Well... Here is my humble advice. Some people may criticize me but I have just recently (Last month) heavily gotten into car audio. If you have 4 open slots in your car then I would recommend the 5.1 or 6.1 Infinity Kappa Perfect component system and power it with a 200.4 Rockford-Fosgate Punch amplifier. You will get very good highs because Infinity specializes in getting very good quality (and loud) mid to high sounds. The tweeter on this component system goes all the way up to 21,000Hz. That is what I am getting within the month so I feel I should recommend it to you as well.. If you have a 6 open slots and a bigger budget then you should get one of the higher grade Audiobahn component systems and power it with a Rockford-Fosgate 400.4 Punch amplifier or 600.4 Punch amplifier. This will cost more and you may lose sound quality (although not a whole lot) but it will be good. However, in my opinion if you have 4 open slots for a mid and tweeter then you should go with the first setup I recommended. Again, I have only been into car audio and I still have more to learn but I have spent at least 1-2 hours a day on the internet looking things up so I am partly reliable but I do recommend you check other opinions. And about Infinity, I am not just all talk about them. I have already ordered 2 Infinity Kappa Perf 10"'s and they will be installed on Friday so I do like the company and their reliability enough to purchase their products. Some other things I recommend is to TALK TO ZANE (He's a car audio genius from what I have seen), listen to as many audio systems as you can (If you go to school find out who has good systems and ask those people if you can listen to them), and keep looking on the internet and see what you are looking for and then search for products that were built with what that in mind. Good luck.
My Car - WWW.SOUNDDOMAIN.COM/ID/ARCANEPARADISE