The Magnum XLS .46A is on sale for $59.99 right now, and it should fly the Nexstar about as wel as the more expensive O.S. .46 AX. The Magnum engines are higher compression, so they aren't as easy for a new pilot to keep tuned in. The Magnum will seem "fussier" than an O.S. .46 AX, but at almost half the price, the Magnum might be worth it if you have help from a more experienced pilot for tuning your engine.