My chip in my '92 325i was located inside the DME which can be accesed on the passenger side inside the engine compartment. There is a little panel that you can screw off thats located all the way to the upper left if you're looking at the engine compartment from standing outside the car. Once you take the panel off there is the DME computer on the bottom and the Automatic transmission computer on the top (if you have an auto). You can take the engine computer out after detaching the wire harnesses and once you get it out you will need a multitude of Torx bits to open everything up. Either way, once it is open the chip simply sits in a socket and can be pulled out and replaced. The EEPROM is the exact same size as the one commonly found on ATX motherboards, so you should be able to spot it rather quickly. Any help let me know.
