In anticipation of the UK iPhone release, I've created a new playlist in iTunes called "iPhone", and put about 6.5-7GB of songs on there. I'll then just sync the iPhone with only this playlist. But, I was thinking the other night - I have a Dension Icelink iPod interface for my car, which I will also be using with my iPhone. Pressing buttons 1-6 on the car stereo selects one of the first 6 playlists, meaning you can quickly switch between them without having to browse/touch the iPod/iPhone itself. On my iPod, I have these 6 playlists set up as "new", "rock/pop", "dance/electronic" etc. So basically I now have 7 playlists in iTunes - those 6, and the new "iPhone" one. The 6 other playlists just have songs taken from the "iPhone" playists in them anyway though. My question is this:- Will ALSO syncing the other 6 playlists to my iPhone send duplicate songs, meaning that if the same song is in "iPhone" and "new" (which it will be), the song will go across twice, meaning also syncing the other 6 playlists will take up a lot more data? Or is the iPhone/iTunes clever enough to know it's just the same song in a different playlist, and only transfer 1 file? Hope that was clear!