-You should watvh the Barret Jackson auctions, a very popular trend lately is taking any vlassic car, it can be a 1940 Cadillac, a 59 Corvette or even an old mail truck and retro modfing it with modern powerplants and electronics.-
The wiring on older planes can weigh hundreds of pounds and is built into the air frame. It is not replaceable without completely rebuilding the plane. You have to route a new wire.
I suspect that newer aircraft have a data bus and do not suffer from this issue.
wire harness on the buff is pretty simple it runs along the bulkheads and spares. Pretty simple to re string wires as they are numbered. most are coupled in groups. same within the wing leading edge panels. Have done many tcto mods while on them.
Sorry about the typos, i agree about wiring.