Welcome to the forums. I don't belive there is much difference in the length of the coupe and sedan. Parked my two toghether one day and it was only a matter of a few inches. As for the road courses, I would think the fwd would do pretty good bacause you'd have the front wheels pulling you out of the corners and not having to worry about the rears breaking loose and spinning out as easy. That's just my thoughts on it. Well, good luck on your search for your GP and you'll be able to get tons of useful onfo here.
