Anything from the ITMS has DRM built in (it's a protected version of ACC, only Apple uses it). And it's there mostly because Apple didn't have a choice - the music companies will not licence music without it. The restrictions Apple places on it are a lot less nasty than some other companies, (like Napster's monthly "rental" of music"). For example, you can burn the files as a music CD as often as you want - or even burn to CD and rerip as MP3 or non-protected ACC.

And, of course, anything you place on it yourself, be it video, pictures, MP3, or ACC, has no DRM on it at all.

As for the Intel MacMini, the closest to TCM chipware is a bios-level chipset to allow installation of Mac OS X on this Intel machine. But that chipware doesn't go near iTunes or anything else, all it does is tell the installer "Yeah, this is an Apple machine, go ahead and install OS X" It's not TCM in the media-control sense though.