If you want to change the time that it takes to shutdown go into regedit and then into HK_LOCAL_MACHINE > System > CurrentControlSet > Control.
In there there should be a waittokill service, modify the data of that (by default it is 20000, i change it to 200) and that should change the time it takes to shut down. You can change how long it takes to shut down so it can play your 5 second shutdown music in unison.
I'm not sure about startup though
Lemme see though.