RE: bye bye trainer, hello GP super sportster
Got one as a third plane after an Easy 2 and an Ultra Stick. Flies fast and straight and responds to control inputs just like it should. I too put the battery pack (6V 1800 mah) in the back. Very sweet to fly, just keep it away from an occupied runway!
I have a really strong MDS .48 on mine and it is a rocket, at least to me.
Regards.