With each conversion... loss. Just put them where you want and you're done. I did that and iTunes sync'd them just fine. No conversions noted here.
Bob
I have several discs of MP3 downloads at various bitrates. I would like to copy these files to my hard drive (via iTunes) without further deteriorating the sound quality. Is it better to copy them as MP3's again, as they are already compressed, or should they be saved in a lossless format to avoid further compression?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic