Cheap CD Player to replace BMW CD Stacker!

[Tymatk]

Hi all

A while ago when i was looking to purchase the X5 E53, i came across one that has a simple, cheap CD player in the trunk where the standard CD stacker used to be ....

How did they do that? I was new to the scene at the time so i didn't pay much attention to it.

I'm sick of not being able to play MP3, AUX on what suppose to be hi-tech SAV unless i have to fork out 2,3 hundred dollars to these add on stuffs.
I could have get rid of the screen and replaced it with a double din, touch screen and everything else but i really want to retain the standard BMW look and features.

Anyone know?