Adding mp3 aux input to 98 stereo via cassette slave?

I have a 98 bose headunit, running aftermarket speakers and amps. Right now I have a switcher that pipes the mp3 player directly into the amps, but when the amps are set to the proper volume and bass it sounds bad when I use the head unit to play CDs.

I know 98s have the unusual radio that doesn't designed for a cassette deck instead of a cd changer so the aftermarket devices don't work. From what I've seen though once you actually have a changer installed you can actually just tap in RCA jacks into the left and right wires, since the head unit detects a device and passes the audio through.

If this is so, I guess the real question is what is a slave cassette deck? Is it something like this?

http://cgi.ebay.com/ebaymotors/Stock-Chevy-GM-GMC-Delco-Slave-Cassette-Player_W0QQcmdZViewItemQQcategoryZ38641QQihZ015QQi temZ250079578256QQrdZ1QQsspagenameZWDVW


It seems to be intended to go into the dash of a truck, but looks like it has a changer port on the back. I know the car has a changer cable in the hatch, so I could just tuck it in back there, splice in some RCA jacks at the head unit, and have a nice aux input balanced through the head unit for ~$20.

What do you guys think?

im thinking you are onto something with how to do this. now you say there is a changer cable in the hatch wouldnt that imply your radio is designed for the changer.

On another note you say you have amps already wouldnt it be easier to buy a ~150 dollar headunit with aux in, etc. Your SQ would also greayly increase

I think all cars got the changer cable, but the 98 and early 99 CD headunits only worked with a remote cassette desk. Only the tape-based headunits could use a changer.

I'd probably get better sound quality but I like the stock look of factory unit, and I don't have to worry about it getting stolen. I'll probably switch though when a nice looking 1.5 din player comes out ... if ever. It seems like only pioneer makes on and it's a few years old. I'd be nice to get one with more modern features like mp3 support, a front aux-in jack, etc.