I'm currently at IU, but I have not done my Emergency Medicine rotation yet... Based on what people have told me, Methodist Hospital is a great place to do your Emergency Medicine... Wishard may have more trauma, but it always appears to be pretty chaotic there, and I'm not sure it would be as great of a learning place. I really haven't heard much about grading. I'm assuming that showing up, working hard, and knowing how to treat common emergencies would be enough for at least a high pass, but don't hold me to that.
I could try and get you in contact with someone who might know more if you would like... just lemme know!