I have a lovely 2011 Avant Quattro S Line on 180,000 miles. I am considering keeping it for another 50k or even 100k miles. What sort of things can I expect to go wrong with it if I do this. It is a diesel and the miles I have put on it (130k in 7 years) are mostly motorway. There is no smoke. Are there any precautions I can take to avoid trouble?