Didn't expect that much debate here! But good to read all of you.
As it seems important, I drive a small car, a Nissan Micra from 2007. The speakers are the ones that come with the car, and they don't sound bad for the car it is, but I would like to improve it.
I was thinking in maybe moving the stock speakers to the rear part, and if it was necessary make'em sound lesser than the fronts. Now I know I would like to cut the high frequencies to make everything sound better.
I am not thinking in a sub. I dont need that much high quality sound in my car, although I would appreciate it. Also, in a small car like mine, probably it doesnt fit.
About the making the car less noisy to be able to hear beyter the music, I wonder if there is something else to do other than working the doors. Is there?
I have everything to do and to decide, but with a pair of good coaxials in the front part probably it is enough.
I am listening to your suggestions!