I have a 98 dodge neon that I was looking to upgrade the sound system on. It is all stock parts except the receiver which was upgraded to a Sony X-plod CDX - GT11W 50W x 4 by the previous owner. I am not all to certain on the size of the speaker, but I think that the doors are 6 1/2 shallow, the rear speakers are 6" x 9", and the middle speaker is a 3 1/2. I don't really know a whole lot about the sound systems of a car, but from what I have read adding an amplifier, upgrading the existing speakers, and utilizing bass blockers would be the main focus. Essentially I am looking for the best possible upgrade in terms of bang for buck. So my question is what parts should I invest in for an improvement in sound quality. Thanks in advance!