IF I'm replacing the original injectors at 147k miles, and IF a primary higher efficiency filter system/lift pump will give me another 150k miles before injector failure, then I'll be a happy camper!
I recently had them measured and two of them were at 2+, but one was at 4+ when I developed a leak that they traced to a HP injector line. As long as they had the top end apart to find the leak, I figured I might as well take advantage of the labor already being done to have the injectors replaced. New injectors. New filter system. Should be good to go for a very long time, if nothing else quits on me!
Still waiting on the evidence that the ADII (or similar) will extend the life of the system. (Not doubting, just anxious to read what you've discovered!!)