If you can be up close on the dash you can notice that the dash cover is retained by screws.
1rst of all you must start removing the cigar ashtray in the middle console,there's also small screw,at the odometer safe glass,there's two or more screws,the under dash right below the steering wheel have screws,the dimer at the low left side next to the hood latch have two screws,but i don't think you have to remove the under dash,just giving the locations of all the screws.
After you locate & remove all the necesary screws you should be able to pull towards you the dash cover,be gentle & us a flat small screw driver to pop out the dash,if you fell that the whole dash's not moving free stop & search for any missing screws,,also there's a piece of the center console that can be removed indenpendetly,it looks like a U surrounding the CD changer,that piece of cover doesn't have any screws,jusy use a small flat screw driver to pop it out.
Ok,so in order to remove the dash cover you must unplug the three active button which is the cruise control,the hazard light & the rear window defroster,special attention on the red alarm LED,before you pull the whole dash out get that LED button out,& squeez it thru the same hole to get the dash,you'll need to do the operation backward all the way to putback the dash board again in place.
Another tip is that the hazard light,the cruise control & the defroster button all have plug-in harness so you will need to unplug them by looking behind the cover & pull them out.Make sure you can ID which one is the right when you're about ot plug them back,don't mix them neither.
Once you successfully have the dash board out you should be able to see how the tape deck & the CD changer are holding in the dash,again,there's no sleeves,only screws & brackets holds the two units in place,whenever you have the new unit you must use the same screws & brackets to hold the new CD player,special attention,don't mix the brackets & screws,put them aside so you can Id which brackets are each one;i'll suggest you that before you purchase any CD player take the brackets & match the holes the CD's players comes with on each side on the case to see if the fit perfectly or will nedd some sort of custom trick to hold them in place onces you're ready to put in the new CD player.
I don't know what you're thinking about the lower deck,but i got a digital EQ in there,looks phenomenal all those lights gigling on the dash.
The digital EQ's are descontinued because all new CD players come with buildt-in EQ,but it could never match a real digital EQ.check the mods forum to see if any mod you may like