I kept my stock wiring for my car to run lights and wipers, nothing else. With the charging system and engine management stuff running on all new stuff the stock lights and wipers all work great off the original wiring.

I am not sure the capabilities of the EFI system you are using but mine runs everything related to the engine and then some. My car only has three switches, Ignition, starter button, and line lock. The EFI handles Electric water pump, 2 fans, 2 fuel pumps, and of course all the normal EFI stuff and Data logging. I used to think all the switches were cool, but no switches is cooler lol.