Non Drive Train Engines

That’s rather complex and adds an unorthodox UI step.
It would be much simpler and more obvious with a separate drivetrain part. Also, separate drivetrain would allow more customization, at the cost of more clutter.

pretty sure clutter is inevitable.

Agree about clutter. Cars are extremely complex vehicles.

there’s a lot of cool ideas that spring to mind thinking of stationary drive trains, rotational energy could be a nice way to kill zombies and other stuff someday.
or conveyor belts and the like even, a cooking area with conveyor belts moving food around.