Technically you would need to code the car to change the VO of the car. The CD changer is listed in the VO as option $672, the iPod interface kit is listed as +IPOD.
Just as a point to note the Dension iPod interface unit works with either $672 or +IPOD so the CD changer may also work with both. Don't forget that there are both electrical & optical connections to the CD changer.
If you forget to connect up the optical connector you may disrupt the MOST optical fibre ring & cause the Bluetooth, CD changer, Nav or Radio/CD/DVD to stop working. It's because it relies on it being a ring of connection.