The oil vapour is fairly harmless as long as there's not too much of it. The exhaust gas recirculation (EGR) is the real problem as it mixes soot from the exhaust with hot oil to make tar. EGR is a particularly stupid response to emissions control since the tiny impact it has on warm-up times and emissions output is completely wiped out by the loss of efficiency and performance once it's blocked up the inlet tracts.
Pre-EGR engines (D2) got a little dirt on the throttle body and in areas of stagnant airflow in the inlet tract, but even at 200K performance is barely affected. The best thing you can do with an FSI or TDI engine is to disable the EGR in software and then remove the inlet and manually clean out all the crud. With the EGR disabled it won't build up again.
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