OK -- lets have some "meat" with all these potatoes. I've been flying the be-jeepers out this exact airplane powered by a Magnum .61 2-stroke for six years. Last winter I pulled off the covering to inspect the airframe as it has been subjected to more high-stress flying that some of my aerobats. I have a bunch of Magnum engines ranging from .46 and .61 2-strokes to .52 and .91 four-stroke. The .52 four-stroke powers a T-34 spinning a 12x6 three-blade prop. No shortage of power there. Back to the Nitro Trainer 60. This airplane is a ***** cat to fly. It flies fast and it flies slow. It is not lightweight but would fly ok with a .46 anything. But why pay O.S. prices when a Magnum .46 is half the price, just as reliable if not moreso, starts at the touch of the starter. Same for the .61. My Nitro has been modified to carry a glider aloft just like the space shuttle hitches a ride on the back of a 747. The shuttle pilot flies the glider back after release. Again, this .61 Magnum is no slouch and has enough power to drag this airplane vertical with authority and it doesn't care that the glider is on it's back. A .61 Magnum is $99 and a .46 is $79 at a hobby shop with the letters HP. Maintenance? None of these Magnum engines has needed repair of any kind. They run well on 10% or 15% nitro fuel. I have a 40 size Big Stik that had a .46AX on it. I pulled that engine to install a .46 Magnum and the Magnum is a better performer. The OP says he doesn't want to stick a lot of money into this airplane and he doesn't have to. I do recommend the .61 Magnum engine just because the airplane performs so well with it. Standard servos are fine. Enjoy. About 3 ounces of lead up front will balance the airplane perfectly with the .61 Magnum.