I tried Sport mode going into Portland, and just left it alone coming out. I was cautious as there was much traffic around so noticed no difference between the two. Would be fun to try in an empty lot. My tendency is to use Sport Mode at all times, if just to save the rear brakes.
Interestingly, I recently read an article that said almost everyone should just leave that stuff (they were talking about the Corvette and other HIGH performance cars) ON. They said that it will save your stoopid ass, as you only think you're better than it is, you're NOT, especially on the track. It really is only the most skilled drivers that can out perform modern car control systems.
That said, I still turn mine down, (not off), as it's hard to four wheel drift with it on. .. (left foot braking)