My TC3 went 58.1 mph on 4s 4000mah lipos and a mamba max 4600 system. This was verified with a gps ziptied to the battery strap. It had a lot more speed left in it, I hadnt even touched full throttle yet when I hit a bump, caught air under the body, and took flight. It was geared 25/69 at the time, next time Im going to try something taller, 30/69 or so. And Im hoping to find a bigger, smoother lot to run on.