I have a TT .46 Pro in mine. It is the best low cost option in my opinion. My next choice if cost wasn't a primary deciding factor would be a Webra .50. The Magnum .52 would be a great choice as well. Optimum for this airframe is the Saito .82. Four-strokes, however are more difficult to install and cost a lot more which I'm guessing is your reason for sticking with a two-stroke. Awesome plane no matter what you choose!