If you think that combustion cars don't have enough electrical and software opportunities, feel welcome to write your own. We write our own engine control strategies for the snowmobile and formula SAE teams. Last year we also made the step to design our own lightweight fusebox/distribution panel/ETC logic panel with SMD components. Not saying that that's a lot, but from there you can go some serious directions. Custom software for traction control, stability control, ABS, engine torque controls, advanced turbo/boost controls, etc.
The engine models and required interactions are a little more abstract than hooking up wires and letting current flow. Fuel injectors, coil dwell, turbos, fuel selection, etc. all have their own non-linear components which can make life difficult. It's not exactly trivial. Even if you run an electric car you can get away with many commercial components: motors, batteries, BMS, controllers. So even on that side of it, you can get away with just hooking some wires up and building a harness, just like the combustion cars.