Did you know that with iTunes Match, some of your files can be updated to higher quality versions from iCloud?
Let’s say you have a bunch of MP3s you ripped from your CD collection at 128 or 192kbps. When iTunes Match does it’s thing, instead of copying your MP3s to iCloud, it serves higher quality 256kbps AAC files to your other computer or devices set up on the same iTunes Match account.
However, you can also also replace the MP3 on your computer with those same high quality AAC files.
Here’s a video showing you how.