You must keep your stock N54 low pressure fuel sensor - you will need to remove your stock sensor from the hardline that connects to the HPFP. It will need to be installed into your port injection feedline, rail or regulator. The stock sensor uses a 1/8” NPS fitting (same thread as NPT but without the taper). If you cannot find a suitable 1/8” NPS adapter for your fuel line setup, you can use a 1/8” NPT fitting by applying a gasoline/ethanol safe thread sealant to the sensors threads. In this case the o-ring will not be sealing the sensor, the thread sealant will.
Fuel systems can be configured in many ways depending on the power goals. We recommend checking out our FAQ and Port Injection Calculator