I have JR ES539 standard servos (not metal gear) for it (4.8kg torque) - will they be enough or should i get higher torque MG servos?
I'd put something a little stronger then a standard on the elevator on all profiles to reduce the chance of flutter. The Extra also flies a little faster then the Katana V2 due to it's slightly thinner wing which makes it track better to practice pattern and IMAC flying. It's more of a do it all plane then just low and slow 3D like the Katana.