I have a HPI Sprint and dropped in a 60amp esc and 3500kv BL motor. It goes like a bat but the motor gets fairly hot (not sure exactly). I want a little more speed and was curious what motor would be best. There is http://www.hobbypartz.com/96m210-3660-4000kv-6t.html which is 10mm longer (hence more torque and run cooler?) or http://www.hobbypartz.com/96m23-car-3650-3930.html which is the same motor that I've got just in 3500kv and it's $10 cheaper. But I would think it would get even hotter since it's a lower torque faster turning motor. Please let me know what you all think!