I have a car he is perfectly welcome to lie on as much as he wants to. But no, he wants to get on the neighbor's cars.
That’s why I’d put something as close to the neighbor’s car as possible for the cat to choose to lay on. Of course, if the cat figures out that you want him there, he’ll never touch it. That’s just how they roll.
I would ask the neighbor why his uber-valuable “collectible” car sits in the driveway.
But if the cat persists, something bad will happen, so the cat might have to learn to live indoors. I built a screen room on the back of my house for my cats. They get to go outside without really going anywhere. That may require declawing to save the screens.