So.....I have been wanting to pull the trigger on new pre-cat O2 sensors.
Here is a link to Amazon for the O2 sensors I was looking at...Great price.
EDIT: I bought these. These are the correct ones:
1 - Bosch 17215 Oxygen Sensor, OE Type Fitment
1 - Bosch 17216 Oxygen Sensor, OE Type Fitment
BMW P/N I need are 11787523434 and 11787523435
from http://www.realoem.com/bmw/showparts...55&hg=11&fg=50