yes... which is what you want to do anyway since itunes by default wants to rearrange how you store your music. So... 2 copies of the same mp3 is best.

iTunes doesn't have to move things if you don't want it to, although in my case I let it do that and have Serato just feed off the iTunes library. When I download tracks from, say, Beatport or Stompy, I save them into a folder by date which I then add to the iTunes library and copy off to another computer for backup (eventually burn them to DVD when I have enough to fill one).

I don't remember the option off the top of my head but it's something like "have iTunes arrange files/music", and you just uncheck that. There might also be one for copying a file when you add it to your library.

Ethan's right, but you have to turn it off or it will screw up your system. I choose to keep the 2 seperate.

You can change those settings I believe. Honestly, 2 copies