Chris, you can solve this problem with a replacing the tank. New the 83 GTI had this problem. You can install part number 533-201-511 A. You will need to install a prepump, but this can be external. I used a facet diaghram pump. You can reduce the tank outlet down with a diesel tank hose 171-201-543 B. It reduces from 11mm down to 7mm. The 533 number is listed as a fuel filter, but is actually a resevoir. You will plumb your pre pump, the main pump and the FI return into it. The last fitting is a return to the tank. There is another discussion of this part somewhere here. I could not find it. Regards