I think you have to weigh both sides. I agree with a lot of the members; I think it is a $40K car, Buick guys are cheap, and you have to weigh the benefit of someone coming to you and wanting to buy your car. That is worth $$$ in itself.
On the other hand look at the car as a means to an end. It IS just a car. It is not a human. Tomorrow is not promised to anyone. If this accomplishes your retirement goals, then that is the end game.
You have a super straight big name car with a big name engine and big name quality parts. I, myself, would be curious as to how much it would really bring. I am not familiar with prices. GNBrett is usually on point with them. But I don’t know if that would sort of be a douchbag move to put it up for sale and see. You would have to be transparent with your neighbor. On one hand I wouldn’t want to leave around 10K on the table and on the other I wouldn’t want to lose $5-8K either. I guess it just boils down to which scenario are you more comfortable with.