help choosing a motor

[RUSTED]

hey,

i want a new brushless system for my maxx , but i cant decided on which kv to get , either the mmm 2200 or the 2650 , ill be only using 4s lipos , and the pinions i have are 20 and 24t and spur 62, 65, 68 , i need something that will remain cool but still go over 40 mph

and im looking for a motor for my crt.5(rcm chassis 2.2 wheels) ill be using 4s lipo with the stock spur and 18 t pinion , i want it to go over 40 mph , i was thinking of getting a medusa but dont know wat size or kv to get ????


thanks