I recently bought a blue tooth unit for an older car in my shop that has a factory radio. It was 35$ from best buy. It connects to your phone and you set it to a radio station that just has static and it plays through there. Does music, GPS, phone calls etc.
As far as bass etc. Most people don't put out enough wattage to power their speakers. For instance, they have a 50wx4 RMS stereo, no amp and speakers that are 100w RMS. You'll never get quality sounds out of a speaker if you aren't driving them.
