I mean like if you have one engine powering the rear wheels and one powering the front wheels. How do you keep the engine in sync as to prevent the rear from revving quicker than the front or vis versa. Even if the engine is exactly the same...won't you have slight variation power? So is the power split determine by the differential like in an AWD system? Same with cars with electric motor on all four wheel. What if motors on one side is weakened, would that not make the car have "torque steer." Wouldn't trying to keep all the engine/motor in sync cap the max power potential? Whats the advantage of multiple engine over a single large or super powerful engine?