If Stern re-did the artwork on Mustang to convert it to a Ferrari pinball, and put a posters up in each Ferrari dealerships, you might find Stern would sell all of their remaining stock of Mustang/Ferrari.
Anyone buying a new Ferrari would likley buy the Ferrari pinball machine as an impulse buy, in the same a normal person would get a coke at the cashier on the way out of a supermarket. What's another $10k on a pinball when you have just spent nearly $1m on a car, and the maintenance/fuel/insurance costs are about $10k per year.
I can hear the words in every Ferrari dealership:
"A matching Ferrari pinball machine did you say? Only $10,000! Jolly good, I'll take it. Do you take cash for that? Great, now where is my wallet? ...Oh darlling, do you think we can fit this in to your home gymnasium?"