For these newer radios its a trip to the dealer to do a radio setup to relearn the vin in the radio to match that of the car, Prices vary between each so you can negotiate them since it only takes a minute. RPO code for the 6 disc is UC6, this will help them do it alot quicker when they go through the menus on the scantool.
Did it sound great thoguh even without the premium sound in the car before it locked?