The Evolution engines come with the Hangar 9 "super duty" plugs.

These are LONG plugs.

The O.S. A3 is a short plug.

Better to use a long plug as the manufacturer recommends.

In the image below on the left you see the long plug used in the Evolution engines, on the right the A3 plug. The other unmarked plug is that used on Supertigre engines.



An APC 11x6 2 blade is about the largest prop the engine will take. Beyond that you start loosing speed and/or thrust.