The CAN bus is a reliable daisy chain network that connects most of the avionics. However it could be a single point of failure so Garmin has a back up data line between an ADAHRS and a flight display. I wired this between the #1 ADAHRS and the main PFD. Now if the primay network fails I will still have all the information I need to control the airplane in bad weather.
I also decided I would put in the second VFR GPS antenna under the cowl and connect it to the MFD. It weighs very little and gives a bit more redundancy. Also both flight displays can share the good GPS data if one antenna is having a problem.
Two VFR GPS antennae:
GSU 25 wiring complete aside from CAN bus:
Back up RS-232 connection between ADAHRS 1 and the main flight display:
