You can just get the two pumps and use hose clamps to secure them on the in-tank bracket. Slit a piece of fuel line lengthwise and put between the pumps to isolate them. There are several ways to run the discharges out of the tank. I Y'd the discharges together and ran them out through the stock pipe, and then used a adapter at the banjo fitting and ran a -6an fuel line to the rail. A better way is to run one of the pumps out through the stock fuel line, and then use a bulkhead fitting and run the second pump to the rail on it's own -6an line. Run a new electrial wire for the second pump (with inline fuse). Use a relay, and trigger the relay with the power supply to the oem pump. You can see pics of how I did it at
www.mkiv.com , go to the tech articles and look at fuel pump testing.