We came to the conclusion that it has nothing to do with what air filter you have.
All 1.8t's have a breather hose at the top of the engine,through this comes oil vapour.This vapour is recirculated back into the intake pipe.What sits right next to this pipe? The Maf.When the dv dumps air back into the intake pipe it's rich in oil vapour,and is passing this vapour back through the maf.Think carbonio woosh
What are your views on this theory?