Hopefully everyone can see the pics now. Sorry for not having them properly up initially.
Pierce330: My car is roughly 5 years and 4 months old, with roughly 80,000 miles. So that averages to about 15,000 miles per year. Daily commute to work is roughly 20 miles each way, of which about 15 is highway.
ZetaTre: Excellent deductions, Sherlock!
I did in fact have a small puddle of oil in the throttle body when the charge pipe was removed, as you predicted. Also, just as you say, the EGR cooler itself only has very light residue (like the tangential intake port). I think you are correct with your ideas and effort on the ProVent. And thank you for correcting me about the terms for the different ports - I have edited my original post and hopefully have it correct now. And your thought about why the tangential intake port is so clean is spot on, I suspect.
Regards.