I am just starting a Tower Fun 51 kit and I am wondering the difference between this plane and Extras. I would like an Extra, but if the profile will have the same abilities, I will most likely wait. When I do get an Extra, I would like at least a 60 size and want to use a 4 stroke. To this point, I have all 40 sized planes with 2 strokes. Should I wait until I am good with the profile or is there enough difference to get one now? Thanks in advance.