I have a 2004 Cadillac with premium Bose sound system, and I am thinking about installing an aftermarket amp and sub. While my dash is apart I would also like to install some form of audio input because burning CD's are inefficient, however I would like to keep my factory head unit because of the navigation unless this process ends up costing more than aftermarket navigation. I am not picky so either would work between a 3.5mm audio jack, an ipod hookup, or a android phone usb hookup. I have been doing research and found the pac C2A-GM24 which will resolve my subwoofer install. I also found some interfaces on pacs website for audio input hookups, however they seem to use the same connections as the C2A-GM24. I did find the IS32 which works on the radio antenna input but I am nervous that there will be static in the sound. Has anyone done this. Any advice, suggestions or help would be greatly appreciated.