Haven't updated in a bit, so I'll share with you my idea. As I alluded to here, there are going to be two groupings of cars; the show cars and the daily drivers (DD).
The show cars are easy, it's usually anything that's a old or fancy car, usually what most diecast car makers make (like muscle cars). The DD's on the other hand, that's gonna be more difficult.
I compiled a list of what DD cars would look great/maybe needed for my diorama. They apparently all exist, but finding them is a different story because most of them are cars that are no longer made. Most of the cars are JL or GL, which is very good because of their quality.
The range of cars is pretty much '00s and '90s cars; which is what you'll usually find here in Michigan. And like I said in a previous post, I need diversity in the makes, models, colors, style, etc.
Also, not too many diecast companies bother with GM cars, do they?