Which specific hoses does the PM kit replace? l checked the ETK and while the E32 750 and the E31/E32/E34 530/540 shared the same piping, the E31 850 has it's own, different plumbing.

Picture on the PM site seems to show the E31 850 plumbing:
http://wuffer.net/bc8s/images/stories/phoenix_motorsport/stainless_fuel_hoses.jpg
It says that while the 850 kit has 4 hoses, 840 kit only has 2.

Here's the diagram of the plumbing for M60 cars:
http://www.realoem.com/bmw/diagrams/i/e/2.png

Seems to me that the elbow (#19) is the most problematic but I don't see how you could replace that as one end doesn't have a fitting..

#19 Doesn't look hard to change at all, Best way looks to remove all attached from the hardline #20 and the filters on each end, Would be easy to swap the small #19's while off the car.

I kinda thought that it looked like it had threaded fittings on the ends..hard to tell.

Not sure how it is on E31 850, but on e32 750/M60 cars, you just shove the hose in to the filter and put a hose clamp over it.

Same with the 8's, The Diagram of #19's doesn't show the clamps that locks the them in place.