A replacement esc is dependent on what you want to run 4s or 6s and what your willing to pay for I'm running this at moment http://www.hobbyking.com/hobbyking/store/__22632__Turnigy_TrackStar_120A_Brushless_Short_Course_Truck_ESC.html
Enough to make it drift but for 4s I'd have to say this bargain http://shopping.rcmodel.hk/esc-and-servos-electronic-speed-controllers-team-orion-vortex-r8-brushless-esc-130a-4s-p-19132.html 6s either hobbywing or take your pick me personally I'd have this http://shopping.rcmodel.hk/esc-and-servos-electronic-speed-controllers-team-orion-vortex-r8-pro-brushless-esc-180a-6s-p-19133.html
And as far as the motor goes it's just see how long it lasts