The airplane was originally designed and marketed as a 30size airplane. Apparently nothing was done when WM decided to sell it as a 40size airplane other than change the labels on the boxes and the wording in the advertisements.

Think about your prop clearance. Fourstrokes swing lots larger props to get their performance. Will the prop you expect to hang on your 4stroke clear the ground?

As for torque rolls.... Don't expect the airplane to do 3D just because you're overpowering it. Look at the size of the surfaces on this WM Ultimate and then look at the size of those same surfaces on airplanes designed to do 3D.