Large cars with big engines plus high mileage at four years old are still probably difficult to sell. I remember noticing a nice looking Audi A6 2.8SE which had been on the forecourt for a good while - just over 4yrs old and just under 80,000m needing a major service including cambelt, for £9k plus. I offered £8k and was refused. A week late the salesman rang me up to ask if I was still interested. I never needed to change its cambelt - still going strong 10yrs and 50,000 miles later when I sold it. Such cars are great value for money for low mileage drivers like myself.