I don't know for speed 3 but I have speed 2 12m, and i am riding with spleene door 159x45 from 8 knots - holding the ground, 9-10 knots slightly upwind, i weight 84kg. all flysurfer speed's have very very good lowend. i recently bought p4 12m couse i don't need so good low end, couse i have speed2 1...