the only time i really know i have a diesel is when cleaning the layers of oil and soot off the back of the car, and when i put the fuel in at the pump. 3 years of driving a diesel and doing everything a petrol engine would (but cheaper), and honestly? i'll never have a petrol again if i can avoid it. the price difference over in europe alone on diesel is enough to pursuade me of that.
ok, so your small gutless standard superminis aren't a great example of a diesel, but they're often not the best for petrol either. there's some substantial technology and environmental advances going on in diesel powered engines at the moment i guess in the same way petrol had a bit of a revolution when they developed unleaded and catal...catly.. cat converters.
i'm proud to take my diesel around the nurburgring. the only reason it's slow is because i can't afford the hundreds of euros for a tow home and the uninsured damage!