I'm interested in seeing if an aos would fix the issue. I have almost the exact same symptoms with excessive smoke on startup and lots of oil in my intake track. This must have been happening to my 04 wrx for some time because when i first removed the hard black line that attaches to the tmic, it was 75% clogged with gunk. Compression test came out good, and it wasn't the turbo for i replaced that as well. I will be replacing the pvc to see of that helps