Always had the itch for the S5 V8 but concerned about running costs and maintenance. I do approximately 300 miles a week, however 80% of that is motorway miles. Am I ever likely to see 30mpg? I just don’t want to fork out something close to £100 a week on fuel. What are main things to look out for? I’m only budgeting with 11k so looking at 57/08 plates at the moment. My other options were a E92 335i/335d but the V8 is too tempting.