Just to say that I agree with you about diesels. Because diesel is a by-product of distillation its supply is likely to be constrained and hence its price is almost bound to remain considerably higher than petrol; so the mileage advantage is questionable, particularly where those who drive only short distances are concerned. I also find that the fragility of turbos makes it more efficient for me to buy a bigger engine that revs less; other things being equal lower maintenance can more than offset any gas savings. Back in the early seventies I bought an 8-litre Plymouth during gas rationing for half price, brand new. Gas mileage was awful but all I ever had to do for 15 years was basic maintenance and I only did about 5,000 miles per year.