The DeatschWerks fuel pump will make sure to keep up with fuel demands well beyond what most will use. As the boost increases in a returnless system, the only way to keep up is to make sure the pump is able to flow the volume the injectors are asking for. The DeatschWerks fuel pump is able to do so in a drop-in fitment specific to the car; while keeping the same stock low profile and relatively low noise levels. If you have a tune from another tuner or no tune at all, please make sure to purchase the according tuning product in the tuning section. This will NOT work without an ECU tune.