Thanks for info, Steve.
The Pedelec power limit here in Germany refers to the output power (torque times revolution)
To get 250 Watts of mechanical power you have to put in more electrical power, depending on efficiency.
Because no police officer is able to find out efficiency or measure the mechanical output power, theres a bit room for cheating
The limit means also endurance power, exceeding the nominal power for a few minutes (going uphill) is not illegal.
But nevertheless, the regulations are strict.
Driving a self build motorized car on public roads is nearly impossible for me, because of the very expensive technical check and permission.
The only back door in Germany might be the so called "red number", a red on white number plate only for car dealer and car repair businesses.
This plate is intended for test drives and can be put on every unregistered car.
But, to being able to request and get one of these numbers, I need a car repair shop, which I don't own.
So I'm back at the beginning
Kai