I assume you meant the MiniMag ???????
Personally I bought the one that you put together, I understand their motors aren't brilliant and I wanted to put a reasonable brushless in it without too much cost. I used the GWS 2212/13T the motor mount then just needed some trimmimg to allow the motor to turn freely but I'm sure you can find an alternative motor that fits straight off.
Re the ailerons, when you build it you install a servo on each wing but if you want can fly it as 3 channel 1st using rudder only, then when you're used to it and want to go to 4 channel just cut the slits in between the ailerons and the wing to allow the ailerons to move and attach the servo's.
Any other queries just ket me know !!