I have a 97 850 with a stock stereo labeled an sc-811. I had the alpine 620 installed and it sounds great. No additional parts are required for the install. I recommend this avenue if you don't mind the trunk mount. Mine is mounted under the top deck so it is still acessible with a full trunk. Again, sounds great and no compatibilty issues. Also the sc-811 has the one through six buttons which are ordinarily used for fm presets. This will act as the cd selctor which makes it seem "right" for lack of a better word. Any other changer selection will require a fm transceiver (i believe its a transceiver) to broadcast to your head unit. Although this system could use a little more amplification. Has anybody used an amp with this setup and if so what amp and how. (Sorry to have asked a question while answering one)

Good luck