Has anyone ever tried to replace the stock lift pump with a different type(not talking about a FASS or any other high speed one like that)? I don't know much about diesels but i'm sure that there is another type out there that would work better...

 

If you do a search on Lift pumps,,,,,, you will find enough posts to keep you reading for years. Some have tried using Holley and Carter pumps. I had my original replaced under warranty @ 45k and then installed the large -8an SS lines. I'm at 102k now and still have 15psi @ idle. I don't know as though anyone has had any better luck with the other pumps lasting any longer.