stock premium stereo with cd slot

i bought my stang with the cheapest stereo option because i knew i wanted to replace it a better aftermarket system (kenwood). my brother, for one reason or another, bought the system with a stereo on the top din, and the bottom din has a single slot cd player.

anyone with the same stereo option as my brother's? of those, have any of you replaced it with an aftermarket unit? what kit did you use? i've tried kits from autozone, walmart, best buy and none of them works. he has about 3 wire harnesses connected to the stereo and 2 wire harnesses connected to the cd slot. none of the kits we bought worked. it powers the aftermarket unit, but there is no sound.

what was your solution?

if it were me id buy a chiltons or a haynes manual and splice the wires myself, its very straightforward, but some people dont like tearing their car apart like that

Can you post a pic of it? I might be able to help if i can see it.