Well thanks...
But the 520 model is without the F.. it's exactly MZ-N520 (CK for Car Kit)
I've read the articles and the look of the N520 is just like the N510... no FM tuner....
I have looked for the MZ-N520 on Sony.com but there is no info about it. On the other hand in Sony Mexico there is a picture and info (http://www.sony.com.mx/netmd?page=todos&top=718&id=740), still I can't find any difference with the MZ-N510.
What do you think about it?