You would need to get into the structure so you would probably want to start by removing part of the tissue, The nose would need to be beefed up to handle the torque and weight of the motor, probably by adding balsa webbing between the stringers, as well as beefing up the wing structure to handle ALL the added weight, which will be considerable. With all that to do, it might be easier to start with a new aircraft kit and make upgrades to it while building. BTW, I didn't even get to the tail feathers