Not very good for 100 tracks, but I usually burn a disc and then re-import from the disc. This also gives you a copy of your purchase. Good luck.
Never tried this but 100 tracks would easily fit onto a dvd, but don’t know if itunes will let you burn audio to dvd.
No problem. A mate and I regularly burn DVD’s of our latest buys and swap them, it’s easier to just import a hundred or so tracks back into iTunes, than exchange fifteen or twenty CDs. We both rip at 320Kb so never an issue.
[edit] in fact, that solves you software problem; just make a playlist of your tracks, which should tell you how much space it needs, then just put in a blank DVD and select ‘burn to disk’
Then all you need to do is re-rip into iTunes and Robert’s your mother’s brother.
You could either keep the DRM originals on the disk as a safety back-up, and delete the ones in iTunes, so you’re all DRM-free, or select them into a smart playlist to not play.