If it's set in or around Chicago, it would most likely be an American car rather than a foreign model. With all the steel mills, auto plants, Teamsters, etc. in the area, there's a lot of loyalty to the US car industry. When I was a kid, you'd get your tires slashed or your paint job keyed for having a foreign car parked in certain places. Obviously that's changed a lot, but there is still a higher percentage of US models in those parts than in other areas of the country.

Some uper middle class kids inherit grandparent's cars when they stop driving or buy new ones. Granma cars are are often Chryslers, Buicks, Lincolns or something like that. Bigger cars, expensive, usually four door models.