Hallgrimur,.the advantage of the mod is that your aeleron "mode" of the flaperon system is at a ratio of 2 to 1,..this reduces yaw induced by the aeleron input,.so less rudder is needed,.the flap system is still effective and better because now with flaps (using the mod) you gain more control with your surfaces ,..less control input get's more results.
the model 3 fly's great just the way it is,..just as the model 2 does as well,..but they do have allot of moving parts in the flaperon mechanism.
changing the mixture on the plane will not make it unsafe,..,.now if you are use to flying it with one control mixture set up and then change it ,..it will be like flying a different plane ,..and it will be a good thing or bad ,..depending on the indiviuals desire in handling that motivated changing the control mixer set up.
I know some say ..if it isn't broke ,..don't fix it but some also say use the "Kiss" method,..keep it simple sir this mod is the simpler of the 2