Hello all, I recently became aware of this 10,000 mile service interval on my girlfriend's audi and dont really understand. I spoke with the guy at the parts counter at the dealership where the first service was being done and he told me that for the free service they just use basic oil, but have the castrol syntec available only if you pay for it. How can they be using regular dino oil and still recommending letting it go for 10,000 miles? We also discuessed weight recommendations, but I figured the forum would be less biased... He didnt really answer my question about how it comes from the factory, but I figured using Mobil 1 0W-40 would be the best choice from what I've read. Any recommendations for the 1.8T engine?