Well fuel penalty is not so bad if you calculate it out, We only do around 10000 miles per year, the additional cost of petrol is close to the lower AP for the petrol car, This will be the first petrol car for many years so we will see. Yes the X1 1.8 s drive is very economical on long runs averaging around 50 mpg, that however drops dramatically if all your running is shorter trips.( somewhere around 40 mpg) Which most of ours are now. plus the problem of DPF filters and EGR valves which dont like short runs.