I know this topic has come up numerous times in the past and I've searched the forum and followed the some suggestions. My car is a 2000 SEL with the 10 disc changer mounted under the package shelf in the trunk. I ordered the PIE X3, harness adapter and longer remote cable that was suggested. The adapter that was suggested does not fit my CD changer, it has square plugs on it while my changer has a round plug. Can someone tell me what adapter I need.