I second the VWVortex. I went to that site shortly after we first got our VW Passat. I haven't been to it in a long time, but as I remember it, it was very informative and it covered all VW models.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section