The Radian Pro comes with a Eflite 30A ESC that incorporates a 5.5V switch-mode BEC(battery elimination circuit). Rated at 700mA continuous service, many seem to think is not adequate to handle the servo system requirements. Even Eflite's own engineers state in their instruction manual that it "Drives up to 5 analog or 4 digital sub-micro-sized servos." The Pro has 6 servos, two ailerons, two flaps and of course the rudder and elevator. Also, I have seen where pilots with on board telemetry have reported current levels in excess of the .7 amp rating.
Reading the online forums it seemed to me that too many pilot's are reporting brownouts and lose of control of their RP's. If a new RP owner had received his plane with control rod linkage as binding as mine originally were, and he chose to fly it that way, he could have problems. The excess load caused by this binding as well as powering to many servos could overload the BEC and the next thing you know, they no longer have control of their sailplane.
Taking all this into consideration, I decided to replace the internal .7 amp BEC with a Castle Creations 10amp external BEC. The following video shows how I did this.
While this modification may not be absolutely necessary, it sure makes me more comfortable knowing I'm not going to lose my aircraft to a overload situation of the BEC.