I don't think a YS 120 will be enough for any of the current 120 size planes. It's been my experiance that at best they produce about 11-12 lbs. of static thrust. The general rule of thumb is that the thrust should be at least 1 1/2 times the weight for unlimited 3-D, anything less does not leave enough power in reserve. I had an Saito 120 on a Kangke Extra-60 and an OS120 on their Cap232-60 Both were a very good match. If your going to a 10-12 pound plane I think the Saito 150 - 180 would be required. I also agree with Chris300s the Extra is a much smoother flying plane and will fly percision the best, but nothing tumbles like a Cap.