Given that these are now very reasonably priced i have started to consider one especially an avant. Can people give me a rough indication of running costs? Average mpg, motorway/town Service intervals how long are they?Average independant servicing cost? Cambelt or chain driven? When should they be replaced. My budget stretches to a car on or approaching 100k miles. I presume 100k on an S4 is nothing? Any parts that are likely to need renewing to freshen it up?