As of version 4, iTunes has a "Replace Existing" option when users are re-importing CD tracks to replace existing tracks. The problem is that iTunes will only allow this option if the ID3 info for the CD tracks and the current iTunes tracks is identical. This script writes the writable info from selected tracks to the info of a CD; when you re-rip, the CD track data is already the way you want it.
(Note: In order to launch this PowerPC-era script on an Intel machine, it must first be opened and then saved using AppleScript Editor, which is located in your /Applications/Utilities/ folder. More information is here.)
Display, create text file listing info of dead tracks
Remove iTunes tracks disassociated from files
Export artwork of selected tracks to parent or specified folder
Set choice of various number tags of selected tracks incrementally
Export info to HTML doc
Search YouTube using tag info from selected or playing track