Importing burned CDs into iTunes

If the original MP3's were de-compressed to make a CD playable in a normal CD player (MP3>CDA) and that CD was then imported to iTunes again as MP3 the files wouldn't be compressed any further as such, ie the resulting MP3's would have the same file size if re-compressed at the same bitrate as the originals.

Quality would suffer badly though as the second MP3 compression would have less audio information to work with than the original MP3 compression had.

Of course if the original MP3's were 320kbps files then it wouldn't be too bad.

Think of how the quality suffers on a photocopy of a photocopy of a photycopy. :)