I know this is an on going topic, I have fuel pump whirling noises, that be said, I've replace both the external with a Bosch 0 580 464 048 and the in tank with a Carter sxo364, and the external is still whining, wondering what people are doing here, the car has m50 injectors and is chipped. Was considering a walbro 255, can I run just the walbro, or do I still need the Bosch In line? Thanks for any help here.