Dontmindme Kinda but they are not standard DVDs so you still need to custom make them. The processes are known, just probably no one interested to make them for a batch of copies.
But I'm thinking, if we know what data is supposed to go on the disc, could one reverse engineer the firmware on a standard DVD writer to make it write UMDs?
Dontmindme In France, heavily modified cars are difficult to legalize because any significant change to the engine, power output, suspension or structure may require individual approval (RTI), which is expensive and not guaranteed.
Man, what's even the reason for such laws? In the UK, you could literally put a plane engine into a car and it'd still be road-legal assuming it passes emissions for the spec of its era. Also looked up Poland, and it seems like all you need to do the regarding power changes is to notify whichever government body so that they can update the registration.

Her dad got it used from some Fiat 500 collector and its a "Giannini" look-alike (not a real Giannini sadly).