I had to finally sign up after stumbling across a link to this forum, and seeing this thread.
I just started working of fixing a 1978 928 that I was given, after objecting to a friend planning on scrapping it for the aluminum and copper.
There are numerous things broken or missing after years of neglect, but one of the things that bugged me the most, was just the visual impact of the intake tubes being missing, and how incomplete it looks under the hood, with them not present.
I think I'll have to model and 3d print a coupler to connect the tubes, and to tie into the timing belt vents, but having the tubes easily available makes it feasible.