Run what you have and then decide what you want. A hatch will tend to be faster because its lighter and has other benefits depending on the class your racing in. As the others have said you need to get the practice first and foremost. You will learn what works best for you and your driving style through racing and you'll be better off for deciding what car fits you better. My group runs miatas but we also have been racing for several years and knew what we were buying. The 240 can be just as competetive but you will be the deciding factor, not the car.