twin fuel regualtors if it is two separate lines. I have single line feeding both sides. If one side has a leak then it will affect pressure on both sides because they are connected at the Y junctions. Pressure is equal on through the lines. Fuel will take the path of least resistance. If you have two fuel regulators but adjusted differently then pressure will be the same on both because pressure equalizes. To be a true two separate fuel rails it needs two separates feeds coming in. I only have one one big feed coming in divided into two smaller lines.
The Supra set up is like mine, parrallel feed with each side feeding 3 three injectors at the same time and exiting out to one regulator.