Ok, fully automated Sleep, Hibernate or Suspend when leaving the vehicle.
One button push or an FE menu Click for Hibernate, then turn the car off and go.
The M4 is made to stop its Hard-off timer and +5 standby voltage is automatically dropped.
For Sleep mode, just turn the vehicle off and go. Standby +5v is now on for the M4 programmed time.
Now I'm in full control of how long the vehicle PC sleeps and draws power or when it hibernates and consumes none.
BTW: Resume from hibernate (after bios post) is now 5.8 seconds with 2GB of ram, 7 seconds with 4GB. I time loaded as - FE displaying and music playing and in exactly the same state as prior to entering sleep.