yea why would u want both? the one you brought "should" be a radio/cd player......do they just make cd head units lmao? why would u want that only anyway....even the cheap ones that cost $60 are a cd/radio

EDIT: ok now that i got that out the way seems like you have the stock unit (just a radio) and now you brought the stock cd player to install underneath, how much did you pay for the cd player? better off replacing the one you have with just one radio/cd player....shouldn't be hard though most likely they're will be a connector opening on the back of your radio for your stock cd player to connect to. My 98 gs-r had the stock acura radio/cd player on top and underneath it was the stock acura cassette tape player lol which i never used, all it was was a wire connecting to the back of the deck, pretty much it