DIY: change of the CCV / Pressure regulating valve / oil separator
The following diy is for a '99 528i automatic. the pictures are for the most part self explanatory of the process, but i will say you don't need a whole lot of tools, mainly torx (2 sizes), sockets: 6mm, 8mm, 10mm, and 13mm some flat screwdrivers and patience.
Just make sure that you connect back all the plugs you disconnected before, there are like 6 of them, but it is easy to find where they belong, they are matched to the sensor.
The result after the installation of the new CCV and hoses is incredible. the car drives way smoother, it accelerates better, there are no more weird noises and the "intake manifold control unit" doesn't shake anymore.