I have a Stingray that one of my flying buddies built. Presently it is powered with a Magnum .61 4-stroke, which is OK, but not unlimited vertical.

I have flown it full, stick wing and now with 1 bay clipped from each wing. Rolls better and I think you'll like it this way. Like the Sig 4-Stars and Mid-Star it flies better with shorter wings.

Another thing I would do if I built the kit is to go to separate servos in each wing. The stock torque rods can bind in the middle and I had to cut out some of the bulkhead.

I would also increase the size of all the control surfaces, 2-2 1/2 inches on ailerons, 3 inches for elevator and 4 inches for rudder.

Keep it light and keep the CG back. If you go with a .61 which is considerably heavier than a .46, be prepared to put the battery in the tail. Even better for a .61 powered one would be the elevator & rudder servos in the tail. You lose a lot of the benefit of the extra power carrying the extra weight, especially when you have to add lead to the tail. If you plan ahead during construction, you can avoid this.

Actually, a .46 to .61 change is not the best. .46s are just about the pinacle of power-to-weight while the .61s are heavy so they can be punched out into light weight .91s like the OS.

A better engine, in my opinion would be the new OS .50 or the Irvine .52. I don't own either, but have heard good things about both. Another idea to consider is adding a Jett or Performance Specialties tuned muffler.