So now I've replaced the fuel filter and pump and the problem remains. I
guess I thought I would post my symptoms one more time before I limp it off
to the only BMW service station around... also the only dealer around.

Engine runs fine, on gentle throttle up to 1500 or 2000 RPM at which point
power is lost, the engine sort of sputters and pops and refuses to turn any
faster, even if I put it in neutral. Thanks to all input thus far, I guess
it's off to the dealer tomorrow.

Matt