Unless you upgrade to a contractor's saw, I think you will have trouble accurately ripping a sheet of plywood in half. Best to do as Silver Doctor says and have the lumberyard do the rough cuts for you. Personally I would aim for the Dewalt or Ridgid..
Mike
Ps even with my contractor's saw, I still do my rough cuts with a skilsaw and guide/straight edge. 3/4 ply/MDF is just too heavy..