I have an acquaintance who works as a top mechanic at VW dealership. He noted the 1.8 engine design had a shallow oil pan, which caused sludge in the engines, and generally stated VW's higher weight oil recommendations are sometimes used as a compensation for potentially faulty designs. I tend to agree in that if one needs high specificity with regards to oil, I question the simplicity and efficiency of the design...Although I guess having specific oils can make one feel elitist, which is ironic that VW was once "the people's car," and not a general upwardly mobile transportation for people who cannot afford a BMW, but want a certain uniqueness with regards to specific oil recommendations.