I just posted on this receintly so you may want to look for it.
There have been a lot of problems with the returnless system. It seems that the pick up filter screen is very small and plugs with very little contamination on the screen. The screen is ultra fine and is only about 2 1/2" in diameter on the bottom of the fuel pump module. I do believe that it is the fuel that is causing the problem but that the car is not nearly tolorant enough of the problem. Most pick up screens are a sock on the bottom of the pick up tube that has a much larger surface area than this little disc.
I have been told (but I have not confirmed) that there is still such a sock further inside the pump module and that by just removing the screen on the bottom that gets clogged too easily that you will still have satisfactory filtering prior to the pump.
If the technician at the dealership is willing (he may feel that it would damage a part that may need to be returned to the factory so he may not be willing), suggest that he remove the screen at the bottom of one of the old pumps and see if there is still another sock filter inside. If so, a solution to the problem would be to just remove the screen that plugs too easily. This is a recommendation that I had from another dealer that was having the same problem.
Let us know how it ends up so we can all continue to learn.
