cd players are being changed out to. Ipod holders that fit inside the radio itself.
as far as radio not fully going back in. most likely you have a jumbo of wires that is causing radio to not go all the way back in. ""or"" the antenna cable is causing things to hang up and not fully go back in. (you can get 90 degree adapters). also some times it requires a very slim long screw driver to push wires back down into an area for the radios to fully go back into the area.
radio is on the list for the 555c. after the full hydraulic change / flushing and getting lens covers for the rear "tail,flasher,turn single" lights.
for the blazer, last radio went out, and just checked, walmart, bestbuy, circuit city, google and a couple other stores that have websites. and just bought the cheapest that i liked. though i think i had to deal with Amps for the speakers. i am think i went for 30 amps per each speaker. total speakers = 4. usb for songs or ipod or other MP3 player. would work on it.
i did go with one that had better folder searching of songs and how it moved across different artists/albums.