monsoon question(s)
You can add an aftermarket changer but it will have its own control head that you will have to mount someplace. It can be connected to the factory head unit in various ways (in order of increasing sound quality) - wireless FM modulator, wired FM modulator, cassette adapter, auxiliary input adapter.
There is one aftermarket changer that will plug right in to the factory radio - the NeoChanger - but I've heard it's not a very reliable unit.
Up until the middle of the 99 model year only the cassette head unit was capable of controlling a CD changer. The single CD head unit had the auxiliary port in back but it was designed to control an external cassette player (available in other GM models but not in F-bodies).
During the 99 model year, the changer capability was added to the single CD head units so that both cassette and CD models could control a CD changer.
In 01 another change was made that allowed the head units to have more than just the CD changer attached to the port on the back (with the proper adapter). That meant that you could have both the CD changer and another auxiliary device like a satellite radio or MP3 player and switch between them with the AUX button.
The buttons are labeled Tape/AUX or CD/AUX in Camaros depending on whether it is a cassette or CD head unit. The buttons are labeled Tape/Play or CD/Play in Firebirds but they do the same function. All Monsoon HUs have these buttons.






