Bear in mind I didn't pay $2099 retail price, I held the SA to a price I found online. He threatened that 'it's not a BMW part, and we will not warranty it'. However, when looking, it is a genuine BMW, and no note was made in the SA docs on delivery. Ces't la vie.

Back flush was done initially by BMW with diesel.

Hard line flushing was done by diesel specialty shop, and included the fuel rail, hard lines, essentially everything downstream of the HPFP.

Fuel has sediment in it. Fuel systems corrode and develop sediment over time. To not trust the fuel filter to catch some remnant metal particulate is a bit of folly, as I feel at this point. Any metal bits in the fuel return line will remain on the opposite end of the system, and behind the fuel filter.

Fuel filters save lives.

E