One other factor to consider is availability of parts for the different cars.
Formula cars and sports racers tend to require more tinkering with at the track and more preparation at home between races. Some cars more than others. If you are handy or a decent mechanic, this should not be a problem. At the track, there are all kinds of drivers and mechanics who are usually more than willing to give advice or lend a hand, part, tool (That is one of the beautiful aspects of our sport).
Quite a few cars are limited in the size of driver they can accommodate.
Go to a race and talk with the various car owners about their cars.
Despite all this, the madness that is racing is tons of fun! Welcome to the addiction