RE: CMPro Swallow EX 90
Look closly at the weight issue and the C of G with that weight of engine, you may need to put the elevator servos at the rear to compensate, I had to do that with a 2S 91 in mine, look bach through the thread and you will see how I did it, I also moved the rudder servo boack and forth to make sure I got the C of G correct without adding unnecessary weight.
Mike