Straight from a email I sent to SHM (Sean Hyland Motorsports) concerning the billet fuel rail.

Jessie,

Our rail can be used as both systems. Returnless and return style. They are returnless out of the factory. If you want a return style, add a fitting on the back of the rail. If you want a returnless, leave the plug in. That simple.

Scott
SHM

Looks like one more part we can to our cars.....