I fly a big stik 60, it is my favorite plane, I am running a super tigre .75 on it and it is more then the plane needs by far. These planes have a huge control surface on the ailerons and are not made for speed. They have a tendency to flutter the ailerons. I can easily tool around at 70+ mph and have unlimited vertical with the .75 running a 13x7 prop.

I truly mean unlimited vertical, with the setup that I am using and some extremely high rates I can flat spin fat enough to climb. In my opinion a .91 2 stroke will just tear up your plane. Get a .75 and enjoy one of the best flying planes out there for a long time.

Just my opinion.