The air cleaner mount should screw off. Save your self some time and buy a extended 5mm allen wrench, it should have a allen head shaped ball on the end of it, should be about 5 inches long. That will make your job easier. Also make sure your injectors have been popped, if not you will have a hell of a time getting your car started! Make sure you put new seals in too. I have done this job a few times as well as a fuel distributor. Its real easy if you have the right tools. Don't expect it to run smooth at first, it will take a while for the system to build up pressure.

__________________
Mike

90 300D 511k
95 C280 133k
14 BMW 528i