E53 OEM CD Changers are manufactured by Alpine. However, it would probably be more convenient to get a CD changer emulator that will play USB stick media.

Regarding the discussion above, there is no part to keep an eye on. There was no CD deck 16:9 for the E53, the only way to have a CD deck in your dashboard was the MID. Furthermore, the E46 CD deck 16:9 does not fit the E53 dashboard and has quite different viewing angle on the LCD.