I just bought the 393DVD player and am not impressed really. It looked better on the internet. Did you ever figure out the ID3 Tag problem? I can't figure it out either. The radio stations display the station ID and Song titles, but MP3's can't?! That makes me angry. I also found the time doesn't keep up. It's always 30 mins to 1hr out the next day. I guess you get what you pay for. 1 day after installing the unit, the SD Card reader went on the blink as well. It doesn't read any SD Card I put in there, regardless of what type of MP3's or WMA files are on it. It worked right after I installed the unit. The USB works fine. The main thing for me is that the DVD player works with MP3's.
Let me know if you figured any tweaks out. I found that holding the SEL button down gives a few more options, but my instruction book doesn't explain what the options do. The only thing is at least I managed to turn off that annoying beep.