Although your information is correct and I understand it, it's not to the point regarding my question (except for using iLO/IPMI/WoL and comparing these).
Since it's a white-box lab without OOB-management cards like iLO or IPMI I am forced to use WoL.
I do understand the ACPI states and I am familiair with them, however it's really just vCenter's time out which bothers me. It takes around 2 minutes before vCenter even GIVES the command to a host to power up, and I want to know how I can lower that value.