Just had the 20,000 mile dealer service, and they suggested an air filter change. Wanted $45 for the filter, so I figured I'd get my own and replace it. Got one from NAPA for $19.95 (and made in Germany), but when I compared it to the original VW filter, the NAPA filter did not have the white mesh pre-filter attached to the paper element. I wasn't too concerned, but later I remembered reading something about a water ingestion problem with the 2009 and later TDI's. I don't know where I read it now, but was wondering if this pre-filter on the VW filter was put there to address this issue? Any input would be appreciated. Thanks.