I think you can install any version of Vista from any Vista install disk... I just installed Vista Home Premium on my friends computer using her Key with my Ultimate disk.
It's legal to download an image of the un-cracked disk. It's only illegal to download a cracked one.
Austinn: Just out of curiosity, what did you download that got you in trouble? And what did they do to you? I have some friends who illegally download stuff, and I might want to warn them. lol