Answer to your original question..........do you want to drive a true racecar, meaning purpose built, full on, handles and corners like nothing else, every part built with the concept of power to weight ratio and a functional efficiency that was no compromise......or do you want to drive a car that started life as a sports car and was then massaged into a racecar?
Either way you'll have fun fun fun
My suggestion is go open wheel - so you'll see how much you like it and if not as much as you'd like or were expecting - well then go back - it's only money and as the expression goes > "ya can't take it with ya"