Report "FM Cassette in it and I would like to add the original factory CD Player that mounts below it. The question I have is can I install any amplifer under the passenger seat or does it have to be the original factory amplifier. If it has to be the original does anyone know what company manufactured it and what other autos might have had the amplifier installed in it. I would like to locate one on the internet if need be and there are none listed anywhere for a 91 Eagle Premier. Thanks for your help. John"