I have an EFlite Pawnee and the recommended motor is the Power 15 but the Power 25 is often used as it is a pretty large aircraft. The Power 25 is a direct drop-in upgrade as they use the same "X" mount. What ESC are you using now? I use the 45 AMP Pro Brushless ESC with my Power 25. It's also made by EFlite and allows more cells and servos than a regular ESC. They're a bit pricey but work great.