As far as I know, not to mentioned enough memory and hard disk space, the only requirement is having a CPU that support Intel's VT-x or AMD's AMD-V technology.

The reason behind this requirement is that MacOS uses some rare x86 instructions that are not supported by the software virtualization in VirtualBox. So, with the "Hardware Virtualization" option enabled, we can bypass this problem.

If you are not sure about whether your CPU supports VT-x or AMD-V, either check it out in Intel's or AMD's web site. You can also check it out in the x86 virtualization wiki page.

Hopefully, most of the new CPUs support VT-x or AMD-V and so this should not be a big problem.