I am back and forth on this project. As many of you know, or didn't know our airbox flows more air than the 1,3, and 5 series N54 cars.
The only N54 cars that flow more air than the Z4 air intake setup is the F01 7 Series and the E71 X6 with the N54, which I am in the process of going through conversion with, test fitment, and clearing which will require converting the vacuum lines and inlets also.
I am recording every single part that is needed including the vacuum converters, canisters. All this in order to maintain the stock parts. Its not going to be cheap. Inlets will have to be after market though and I am working on that also to be an E89 Z4 complete kit
A more simple solution is this also that I have been working on is modifying the current Z4 airbox to allow more airflow.
Things are very slow on the two projects, when I am slow and bored then I revisit them