My self and another racer have smoked 4300's using the Sphere. The thermal protection to the motor seems to not work. And then my Sphere quit working.
So I went 100% Novak and have had no trouble what so ever. I would stick to the GTB and the assortment of motor options they have. But this was all before we started using the sintered rotor, I would guess that may help but it would be risky.
And the wiring is all the same, (ABC compatible).