How to replace an MP3 or M4A in iTunes with a higher quality file, without having to re-do playlists containing the track?

I have in my iTunes library some songs that, years ago, I ripped from CDs at bit rates of only 128kbps. Storage is cheap now and I'd like to replace those songs with higher-quality versions (e.g. 320kbps for the MP3s.)

I do intend to re-rip some of my source material (the music I listen to most often) at the higher bit rate. I don't use iTunes itself for my ripping; I use another ripping tool.

Is there a way in iTunes for me to replace the lower bit rate version of a track with the new higher bit rate version, without having to re-add the track to playlists already containing it? Could I just slip in the new version of the MP3 (assuming same name) with a filesystem copy, or is that liable to cause problems in iTunes? How can I avoid having to manually copy metadata or manage playlists affected?

p.s. I already know about iTunes Match. Please assume (for the purpose of this question) that I'm not interested in the automatic upgrading it can provide. Looking for a solution that will work without Match, or when Match can't upgrade a track. Thanks.

You can just replace the file in the filesystem.

Unfortunately, iTunes is too clever for it's own boots and registers for Finder events. So renaming a file in Finder will update it's location in iTunes if iTunes is open!

So here's one way I've tried that works.

1. Quit iTunes (actually quit, not just close window);
2. Locate the file in Finder:
   • This could be done in iTunes (before quitting) by right-clicking and choosing Show in Finder;
3. Replace the file in Finder with one with the exact same filename;
4. Open iTunes

iTunes will then use this file when you attempt to play it. Note: if any of the ID3 tags differ they will be updated in iTunes too (which is probably what you want). This means if you replace it with a file with the same file name but with less information in the metadata, you'll have less information in the iTunes browser.

I wrote a python tool named replica that automates the task of replacing file while keeping id3 infos of the old file. pip install replica to install.
My use case is that I often download upgraded versions (bitratewise) of my favourites mp3 albums and am particularly interested to keep my ratings (that i duplicate in the grouping tag).

Usage :

If you replicate full albums, please make sure that tracks filenames are similarly ordered in both source and destination folders.::

$ replica -u Library/Sam_Cooke-Ain_t_that_good_news-128kbps-2003
Incoming/sam_cook-good-news-320kbps   
Cloning id3 metadata... Done  
Renaming files......... Done

In addition to id3 cloning, replica can handle files renaming too so that upgrading mp3 files becomes a no-brainer.
Consider the -u option to remove the source files and replace them by their upgraded version. Preserving filepaths enables you to migrate id3 metatags to new files while keeping the information stored by your music player (such as ratings or play counts) valid.

Upgrading iTunes files to higher quality without losing metadata

Turn off iTunes Match.

Rip higher quality version to iTunes.

Go to higher quality file. Right click - Show in Finder

Go to file to be replaced. Right click - Show in Finder

Quit iTunes

In Finder delete lower quality file - move to trash - empty trash

Drag higher quality file to where lower quality one was

Open iTunes - play track from location of old file

Song could not be found - locate

Repeat

Now you have duplicate images in iTunes. To delete these you need to follow these next steps.

Highlight all the redundant tracks in iTunes. Delete. Delete Songs. Keep Files.

Turn on iTunes Match.

Bingo.

The currently (March 2019) chosen answer is from 2012, and the other answers date back at least to 2014. This thread ranks high in Google search results for this problem, so I thought it would be worth pointing out that, in some circumstances, current versions of iTunes make this much simpler. If your new tracks have the same album, artist, song, and genre, when you import them into iTunes, then iTunes will recognize that they are duplicates, and ask if you want to replace the old versions with the new ones. Doing so keeps the current metadata, including play counts, playlist membership, etc.. Even the "date added" metadata is retained, keeping the original add date ("date modified" will be the current date).

I just re-ripped tracks from a CD I ripped back in 2005. The 2005 rip was done using iTunes's MP3 encoder; the new ones were done with iTunes's AAC encoder. Even with the different format, iTunes recognized the tracks and offered to replace them. After the replacement, I verified things like add date, play count, and playlist membership for the files. It worked perfectly.

I learned of this from the MacWorld hints forum: Replace Songs in iTunes with Higher Quality Versions Keeping Stats - Mac OS X Hints.