Try running it in VMWare first since VMWare will still take into account your physical hardware, so try putting it into VMWare and see if it works. If it does, test out the performance before dedicating an entire partition into booting Leo OSX
IPSW is the extension of system related Apple files to simplify.
Piracy is unfortunately not supported. You can probably find the image on those sites, but you will run into problems. Best option is to get an OEM if you're going to fully commit to the OSX multiboot. You have to jailbreak first in order to use UltraSn0w to unlock