I've had my S4 near 2 weeks now and have a few questions, I wonder if anyone can answer? S-Tronic... In the service book, it says change s-tronic oil and filter at 38k. My car will need this in about 9 months I think. I was speaking to a guy at Audi regarding service plans and he said the filter didn't need to be changed, even though it says it in the book. He was adamant. Is this right? Should I insist on it when the time comes? Exhaust - The previous owner was less than loving to the quad exhaust... it's filthy, covered in carbon deposits. I have tried metal polish which has taken some of the minor/moderate stuff off, but I'd like it as close to perfect as possible. Any suggestions for products to use? Fuel additives - are they just a placebo, or are they of use? I run the car on 99ron (where possible) Thanks in advance.