The 4 M3 screws are for securing the butterfly plate to the spindle. After screwing them in, put the M3 nuts on the other end. Last step is to punch the threaded end of the M3 screws in a "+" pattern, in order to prevent accidentally fallen of the nuts in the engine. I doubt that this will ever happen, but it is just a safety measure. Also, when punching, remember to put something to hold back on the screw, otherwise the shaft might bend! The 2 small o-rings are for replacing the ones on your BBS (idle brass screws) in case they are worn. If you have any other questions, please feel free to ask me. Thanks, Dan.