when it comes to the premium sound system in the 3rd gen 4door it is tricky. The option was available for the 4door and i have seen it in the wagon. With the wagon there is no package tray to mount it to so premium sound would only consist of the amp with the 80w output it offered as compared to the 24w output of the standard head unit.
4 door cars could also be ordered this way and not have a cd changer installed. The difference between the 4door and the wagon is that the 4door is equipped with premium sound without the cd changer has the wiring end for the changer present in the trunk area which would have the changer installed. So if you were to purchase a car with premium sound head unit it is important to ensure it is premium sound by checking under the driver seat for the external amplifier. If it has both of these things then it is probably a true premium sound factory install and the changer can simply be installed. Bonus points if you have the correct 4door mounting brackets (2door uses different brackets).
there is also the off chance that the person owning the car replaced the head unit and thought they were all the same and found out the hard way that the connectors are different and is not plug and play for non premium sound cars
i have had many cars with this option and now i sell the radio faceplate adapter to replace this with a plug and play premium sound bypass harness so if you get this car and decide the trouble in finding the correct cd changer parts is not worth it and want to put modern radio in its place then i can provide the parts necessary
