You will have to make sure that the motor you replace it with is a simular size. You will want it to be the same or have a better KV rateing and you will want it to run on the same voltage.
It is good to check also that the ESC is compatible to the motor that you intend to replace your stanard with.
Allso be aware that not all brushless motors work the same way. some have a outer case that spins and the ones used most have the inner workings spinning. There are also different types of speed controllers. It is somthing that Even I am still doing research about. So take time to learn more about them yourself after all we are the ones that will benifit from our efforts to do so.
