RE: Aerobird Extreme motor upgrade available?
The Aerobird Challenger was my first plane. After many other planes, mostly in the brushless arena I decided to go back and tinker with my challenger. After many mods I decided I wanted to go brushless. Rather than scrap the stock electronics I installed a [link=http://www.modified-rc.com/brushed2less.html]Brushed2Less[/link] controller onto the stock setup and added a brushless speed controller and a Mega 16/15/4 with a 7X4 prop. That was definetly overkill. The thing was now a rocket. At half throttle the tail would still provide manuverability, but any more throttle, and it would only go strait. The V-Tail could not handle that much air over it. It was fun to fly. I would do half throttle tricks and then point it strait up and go full throttle. If I wanted to really spend more time flying that plane I would pick a smaller motor.
I know you are talking about the extreme, but this is another option.