A pro setup might have too much steering. As you learn throttle control you start to want more steering but that usually frees up the rear end. For someone new it tends to be more forgiving and result in faster lap times if the car pushes a little more. It forces you to slow down for the corners and you spin out less. It if faster and more consistant to slow down for a corner and acclerate out then to go hot into a corner and spin out and have to turn yourself around! I would say that would be the biggest difference from what I have seen. A veteran seems to always want more steering.