Mine runs through the onboard sound and into the RCA inputs in the my headunit. The SQ is a little crackly (background noise only and difficult to notice when the music is going), but I'm trying to get to the bottom of the cause of this still as it could have to do with the routing path of the RCA cables, I've tryed a few different paths with no improvement, so I'll see if a noise filter will do the trick (there is engine noise from the alternator too). The biggest factor for music SQ though is the program that plays the music as they all differ in the way they process the data from the MP3, WMA, etc files and have differing clarity. I've found that running my music through Roxio player or Musicmatch (Yahoo music player, the bastards ruined otherwise awesome software though) I get better SQ then through the Centrafuse Media Centre (which I think used a Winamp derived system.