[squeeforever]

well the advantages to the xl's are the longer can which will provide much more torque than your 9 and 10l which will allow you to gear up thus run a lower kv motor to draw less amps and get better runtime. the lehner 19 and 22 series motors are motor expensive because of higher quality, tighter tolerances and segmented magnets which will give you more power and higher efficiency which in turn give more runtime. on 14 cells, runtime not being a issue i would go with a 6xl for shear speed but if runtime was an issue i would go with a 9xl which you can gear alot higher to have almost the same overall power but have more runtime. but yes, the 6xl will give you more speed. i would personally stay away from the lehner xl basics because they wont have as much torque as your 9 or 10L and will run somewhat hot.