E38 loud fuel pump.

I'm dealing with a very loud noise which has been diagnosed as the fuel pump on my 97 E38. Problems began after gas tank implosion. Indie bmw shop replaced with used tank, and new fuel pump(aftermarket). Car ran well but pump would get very loud when fuel was near 1/4 tank and wouldn't run well. I thought I could live with that but after a few months the noise became constant, even with tank full. I changed the fuel pump and check valve with OEM/BMW parts and car ran quietly for a half hour or so and the noise returned. The indie shop that originally did the tank and fuel pump says that the other hardware in the tank was fine and they tell me that they changed the fuel filter as well as verified that the fuel rail wasn't obstructed. I do have pending replacement of coils on cylinders 1 and 2, and a new air intake boot to install just to provide more detail. Anyone had this loud fuel pump issue solved outside of replacing the fuel pump and check valve?

E38 loud fuel pump.