I've been running FMS 13 via Parallels for a while now. Works quite well
One question for the Server experts.... The physical machine I'm running on is a 4-core machine. Should the Parallels VM also be configured as a 4-core machine? It can be configured with more if I want but I'm not sure if the virtual cores should out-number the physical cores. I've always had it configured as a virtual 4-core machine. I know Server like more cores available to it but I wasn't sure if it was the optimal configuration.