It just get me confused when my FF hatch back sells in Muscle grid or a hardtop car sells in convertible markets…
Is the market grid contents the individuals who wants to buy this type of car most, but still acceptable for similar model, or one individuals could be in different grid if he wants or even affordable for both type of cars?
For example a family guy who still love soprt cars, could he be in “famliy sport”, or if he decied to have two cars, be both in “family” and “track”?
FF in Muscle or hardtop in convertible markets simply means there’s not enough strong competitors there yet. It means that either your car is exceptionally well built, or that a competitive market hasn’t been established yet.
It’s why anything with horsepower in the 1940’s seems to make a hyper car, and why anything with a truck bed can make both Muscle and Heavy Delivery at the same time.
Fear not, the beta testers are in the process of making thousands (literally) of models to cover the market much better, along new improved balance that will better differentiate several of the classes. Plus it’ll be segregated by difficulty level, and I can assure you, once I’m through with this lot, it’ll be MUCH harder to make anything an ultra competitive hypercar 
Well, if the market stands not for individuals, one could simply say: "OK, there is no convertible sport car I want, I’ll go to the sport car market and see if there is a car I could accept. " Then the convertible car market would still be 0 intersts in my hardtop car.
But, if the market is stands for indviduals who wants that type of car most, while still accecptable for other types, things could be kind of mess up, you can still try to sell hardtop car to one (not so despairly) want a convertible car. as long as your car is good enough. Also, how could the markets be for people who could buy multiple cars, they may want a super and a luxury and a Premium Offroad…