The OE Nissan and equivalent size oil filters are designed for light weight oil, OE spec is 0w40. As the viscosity increases the factory filter begins to become a restriction to the thicker oil.
Most filters have a bypass that opens around 10psi differential oil pressure. What this means is when the pressure on the inlet side of the filter becomes 10psi higher than the pressure on the outlet side of the filter, the bypass opens and you get unfiltered oil passing into the engine. This is bad for obvious reasons.
The WIX Racing filters are designed for thicker racing oils and higher oil flow rates (which comes with increased RPM).
The increased surface area, and increased flow capability of the racing filters ensures less pressure drop across the filter and in the case of the recommended 51060R WIX Racing filter, there is no bypass, so 100% of the oil is filtered 100% of the time.
The Oil Filter adaptor includes the conversion base, threaded filter boss adaptor, and a WIX oil filter of your choice. The threaded filter adaptor is female on the OE side, and has a retaining clip to keep it together with the conversion base. Once installed, the base and threaded adaptor will remain on the engine during oil changes, making it a simple on/off filter change for oil changes.