Hi All, New to this and first post. I've just recently purchased a 2003 E-class 220 CDi (W211) and noted in the manual that the fitted Audio20 can play MP3's. My car has the single CD player in the head unit as well as the 6 CD changer below it. I have tried burning several CD's (TDK brand) and am unable to play any of them in either units. Can anyone help please with my questions below: 1. Does the car need any software upgrade to play MP3's and how do I find out if mine has this? 2. Has anyone created their own CD's and got them to play them? If so what CD burner software did you use and what settings did you have? 3. I've read in other posts that the W211 has an AUX socket in the glove compartment. Is this standard and where is it? Mine just seems to have a black plastic cap in the area where others have said they have a jack. Many thanks.