In case someone wants to rerip old albums in better quality changing also the file format is quite possible.
I have done this many times:
I have an old album that I have ripped in MP3 format. The files are perfectly tagged, but the audio quality is not good enough anymore. I want to rerip it in the Monkey's Audio format.
At first I rename the old album files (which are in a separate album folder) from properties using [Track #] as the only rule. Then I use the Find and Replace tool for replacing the .mp3 filename extensions with .ape.
Then I rerip. I rip into a temporary folder and use again [Track #] as the only rule.
I get filenames like this: 01.ape, 02.ape, 03.ape, etc.
After ripping I remove the new APE files from the library (or use a temporary library for ripping).
Then I replace the old files with the new files using Windows Explorer.
Inside MC I need to do three quick steps for the now replaced files in this order:
Update Tags From Library, Update Library From Tags and Rename Files From Properties (using a proper rule).
The last step is to reanalyze the files. The difference is usually very small, but I want it to be perfect.
In this way I can preserve all library information, including the statistical information and original import dates.