Brushless mad force with 3 speed?

as title, i just recieved a mad force and its nitro... yuck,

ideally i would like to keep it as a 3 speed, as their cool ;)

i'm thinking elektriclutch and custom motor mount, i will be running 4s but i'm not really sure what motor to go for, i was thinking something in the reigon of 2000kv, should that give me similar performance to the gx21 thats in it at the moment?