If I can suggest something, contact a local shop that does conversions of police cars. They might be able to help you setup a external speaker that uses your factory sound system. The local pd here has a couple of the new cars setup this way. They hear the local dispatch on the left side and the county on the right side. I have a 05 with the shallow armrest that I really want to convert into my radio box. Your pictures have given me a couple ideas on how to do it now.