I have a 2002 Ford F-150 CrewCab and I want to improve the audio quality. Hearing the songs on my iPod vs. the songs in my truck is like night and day. There is so much more clarity on the iPod. I know for sure, that I am going to get a subwoofer that is in a custom box that fits under my backseat. I want to get new door speakers. But here is where the question comes in. I have a 6-disk CD changer in the backseat. So I'm not sure if I want to give that up for an aftermarket CD player. I heard that the factory radio that comes in the vehicles are designed especially for the best quality for that vehicle because they are factory fine tuned for that vehicles airspace. If I were to get an aftermarket radio, would it worsen the quality? Or will I notice an improvement?