Windows 8 compatibility is limited to some Macs. You can check what Macs are supported in this site > http://support.apple.com/kb/HT5634
In those Macs that don't support Windows 8, you get a message when you download the Windows support software telling you that you can only install Windows 7 on the computer
The good news is that even though I got the message when I went ahead and installed the Support Files / Drivers on the BootCamp Win 8 64 bit that I had been running for a month, all the minor problems were solved. So if you are willing to assume the risk (and have a recent backup) you may want to try installing Win 8 and use the Win 7 Support Files in an Intel based Mac. Honestly I have not found a single problem, the Win 8 runs better than my previous BootCamp Win 7 install.