What's the best way to transfer ALAC files between computers when subscribed to iTunes Match? I've pretty much uploaded everything to iTunes Match now, but my collection is across two computers and so it has merged everything together... Which is fine. However, I was planning on moving some of my items from one computer to another (i.e. from my smaller iTunes Library on the MacBook to the main iTunes Library on my PM G5).

Since it is all nicely synced now, I've discovered that if I use Home Sharing, then transferring the files manually seems to duplicate them on iTunes Match. So instead of doing this, I'm downloading them from the cloud on my PM and then deleting them on the MacBook once they're done... All good so far. However, a bunch of my music is in ALAC and so I don't want to do it this way because I'll end up downloading the files at 256kbps AAC instead.

So I just wanted to know, is there a good way of getting already-synced ALAC files from one machine to the other without having to get iTunes Match to re-sync them all over again?
Turn off iTunes Match on the PowerMac.
Use Home Sharing to move the ALAC files to the PowerMac.
Re-enable iTunes Match on the PowerMac.  It should re-scan the library and match the ALAC songs.  
Don't ever delete the ALAC songs from the PowerMac, otherwise your only choice will be to download a 256Kbps file from the cloud.