Cooler air in the engine will yeld more oxigen to burn and you need more fuel.While the stock rev1-2 is running pig rich, it will be lean, and at the same time the injectors will be close to maximum, or over the maximum.
Whatever you do to rev1 and 2 the piston
#3 will be leaner then the rest because of the intake manifold design, and the stock fuel rail will drop pressure towards the piston 3 and 4.I woud say a Fuel pressure regulator, a stock fuel rail modified to double feed or center feed, some kind of engine management modification is needed along whit a lager fuel pump, because if you bump the fuel pressure the stock pump won't be able to deliver enough fuel.