Does he park in his driveway at night? Could you approach without detection late at night? If so, I suggest applying gel paint stripper to his car. Be sure to get a nice smear on every panel, the hood, the roof, the trunk....make sure the whole damn thing will need re-painting. If you work fast it would take about a minute. If he runs it through his insurance, his premiums will go up and it will cost him a lot over time. If he doesn't, it costs him a lot all at once. Either way, he isn't enjoying spending your 779 dollars, because it will cost him far more than that.
Here's an example of what it can do, and keep in mind these guys used standard liquid stripper...a lot of it ran off...a gel will stick to the vertical surfaces, allowing it to strip right down to the bare metal. They also missed a lot of areas: