Holes for the fan outlet and inlet, alternator lamp, USB connectors and main switch were pre-drilled. There's an option to add a digital volt meter, if there's room on the near side. The fan is placed right over on the top right side as it was thought it was interfering slightly with the MCU serial connections in the previous version of the lay out. All the different sized strain relief grommets are in place, ready to start the heavier wiring. Layers will be wired up one by one and all the high side switches and relays will have connections made to the outside of the box so that the next PCB layer can be installed without having to worry about going backwards to the previous one. It looks tidy at the moment, but adding the wiring will make it much more confusing, if it were not for careful labeling of each wire.