I have just purchased a MT P51, i installed a OS 46 FX , has plenty of power and speed. To prevent the engine from overheating , I had to cut out a section in the bottom of the cowl to increase air flow to the engine. Also make sure to go over ALL of the covering with a heat iron. The mechanical retracts are ( fair ) the steel gear is a little weak , and tends to bend ,even when taxing. Over all, i love the Model Tech arfs, they fly very well. I have had 2 Sukhoi s , and this P 51 .All have balanced perfectly, and needed very little trim on the first flight