The .40 LA is a reliable engine but about as exciting as a hamburger bun.

Check out the Thunder Tiger Pro-46. That's a hot little package for the price. I put a Perry carb on mine and it truly IS a hot dogger in my Goldberg Hot Stik. As much plane as I can handle.

I had a Super Tigre G-51 with an 11X5 prop and that was a perfect marriage with my Kangke SK-50. Fast and maneuverable. Lost her last October at a fun fly coming in upright for a limbo event. Did a half roll at eye level at full throttle, made the inverted pass and touched a wing tip to the ground rolling back to upright at eye-level . . . almost. What looks like a true lineal roll at 100 feet appears less so at six feet. Talk about a re-kit. Hot-dogging and dumb thumbs at their finest. The ST51 was a bit finiky but an optical tach helped immensely. Mine prefered 10% Nitro over 15%.

Speaking of Kangke. I have one of their .50 engines that was a P.O.S. 24 consecutive dead sticks. The club two-stroke guru pronounced it "impossible to tune". Then I swapped out the carb for a Perry. It's right up there with the ST G-51 now! I'm really a fan of those Perry carbs. I ended up with one on my Thunder Tiger after a dirt nap damaged the needle valve collar and I couldn't keep it tight. Added about 800 rpm to the top end and it gets there quicker (no lag). They are VERY finiky to set initially but once set are contented with most conditions.