O2 sensors are generic technology - they even all share a common screw thread - e30's use a 4-wire model, any brand should work as inputs and outputs are the same as long as you get the wirng to match up right
the four wires there will be two wires the same colour - they are the heater (not polarised)
one wire is earth - shorts to the outside, test with a multimeter
the other wire is the signal - if mem serves, signal is usually grey
3-wire ones are missing the earth - not a great idea to use a 3-wire as the exaust manifold is not always a great earth watch for the shape
of the sensor probe - the OEM bmw one has a rounded end - many 3rd party ones have a squared off metal sheild around the sensor probe that will stop you from getting it to fit!