What benefit would you see going to a larger tire? As the tire size gets bigger, the rim size stays the same, and the beads essentially get closer together than their specified width, making the tire give you a smaller and smaller contact patch. You could probably go with a lower profile tire, same first number, or maybe one down, smaller second number, then you will get yourself a larger contact patch for street only.
Bottom line, larger doesn't mean more rubber on the road.