This PNP Kit bypasses the factory voltage limitations on stock wiring by direct wiring fuel pumps to battery. It'll increase power output from 12V to battery voltage (14V+). With direct battery voltage your are now able to maximize the pumps flow, allowing for more head room on cars with injectors that are maxing out.
A not so well known issue with hard wiring upgraded fuel pumps is it can overrun your fuel pressure regulator at idle, causing your fuel pressure slowly to rise when it shouldn't. This kit solves that problem because it still allows the fuel pump controller to switch the primary pump from low, medium and high speed.