A lot of jap cars it is. In japan most places don't sell FCD on their own. usually come with fuel controllers too, as mentioned, they trick the ecu by raising the limit, so although you're running say 15psi, the ecu is only fueling for 13.5psi (or whatever the cut off is) which is where a rrfpr, ecu or fuel controller come into play. As mentioned its there to protect the engine, so best not remove it unless other mods are also applied to compensate. It's also not a good idea to keep hitting fuel cut either when it is there.