There is a need to address the question about Smart Nav and Smart Nav Plus.  The easiest way to determine whether you have the plus is to look for your AM/FM antenna connector.  If you have a standard Motorola-style antenna connection, you will use the connector BT ISO DIN.  This connection is found further down in the wiring.  Follow the wires from the old connector about 6-8inches down, and you should see two 8-pin connectors.  This is where our BT ISO DIN will plug in.  If you don't have a Motorola-style connector for your antenna, you have the 1st version of SmartNav and use the SmartNav + Ant Adpt or the SmartNav + Ant Adpt. PLUS, that comes with a radio removal tool.