These Malpassi / FSE fuel pressure regulators are designed for use in EFI vehicles, both factory standard and modified. With this particular model, fuel pressure increases at the rate of 1.7:1 with manifold pressure (or boost). This means you will get a much richer top end than the factory fuel pressure regulator or most aftermarket regulators offer. In some instances this may mean re-tuning or re-chipping to make use of this extra fuel.