Dual ECM installation

[skydawg]

Read that installing 2 ECM's, one primary & other as a back up, is possible. Anyone ever done this? Would 2 ECM's on same harness, except for having their own sensors, work without issue and over time? Saw a post that a race car had a automatic switch that swapped power only to back-up ECM when a fault was detected in primary ECM.