Actually you don't really "know" what you are talking about. They beat BD, SCV and Cadets at finals this year, in drums. What more do you want?
Now that that's out of the way, you are trying out for one of the best quadlines in the world with no corps/WGI experiance. You need to be seriously bringing it at auditions for them to even look twice at you. Im not trying to discourage you, but I think you should have a back up plan of where else you can march.