[suicideneil]

Indeed, the feigaos work best in the 30-40,000rpm range- if you used a 9L on 6s lipo and geared down that much it would overheat due to undergearing ( not enough load on the motor ). 4s sounds fine though, but for 6s you'd want a much slower motor & gear for the same speed- should be able to use a smaller batt as a result due to increased effociency to get the same runtime as before ( or use the same sized lipo as before mah wise & get more runtime ).