The car I am upgrading is my girlfriend's 2002 Cavalier. The stock speaker sizes are 4x6 up front and 6x9 in back. I planned on replacing the front with a component set but I am not sure of one that would fit. The 6x9s I have no idea what to replace with, either a 6x9 or a 6" I assume. If it helps, I plan to spend around $500 on the speakers and an amp. Also, the bass isn't the main focus, but is neccessary. I would like to have a nice balanced sound, with crisp highs and relative mids and highs. Any suggestions on sizes, brands or models are greatly appreciated. thank you.