including tweaking the engine, the electrical system, the fuel pump, etc. Sounds like a lot of work? Maybe. But it’s better than building a car from scratch.

that would be more of a rebuild than a fork. If your end product is more similar to the OEM car than it is to the end product. It’s more like a fork. If the car is more akin to a custom built racer, than the OEM, it’s a rebuild.