I (as you know) have a '84 318i and dont get that great of mileage either. I would test the TPS. Also my afm does the same jumping around yours does. Im sure that is playing a huge part in fuel consumption. I too have replaced near the same things you have. However when i rev match i dont experience what you say.
I know that i need to time my car correctly though. I just did it by ear. Misses slightly around 47-5 also.
Considering the age of our cars i always have this hunch that the distributors are old and tired but i havent took the time to test mine yet. The coils are fairly bulletproof in my experience with these cars.