Link to e90 forum with some good diagrams of the turbo system, albeit for the 335i.....

2007 Engine Tech: How the N54 works (must read!!!) - BMW 3-Series (E90 E92) Forum - E90Post.com

Still useful info. Makes me even more concerned that there is oil in the charge air hose. If they just sealed the oil in by replacing a seal, is this going to go into the intercooler and clog it up? Is it going to go through the intercooler and back into the cylinders?

I have a lot of questions to ask the dealer...I am wondering if I should be asking BMWNA to answer to this question...

I wonder if there is a faulty seal INSIDE the turbo that is seeping oil. Will this oil foul the impellers by caking onto them and eventually causing imbalance and failure?

I'll try to get more answers......Thanks Ard for piquing my curiosity!:thumbup