remember we have 70mph max limit, and you could get away with 78 most of the time. The supercars are useless as supercars on the road [for going fast]. Now go back to my post and find "EXPENSIVE" at the very start. Audi R8 or Porche 911 is not exactly an affordable commuter car.
Diesel excels at the usual everyday grunt, where one would need an almost supercar to match some of that low end power.
The "grunt" is due to forced induction rather than the fuel, as the numbers posted by nilagin demonstrate. Note how the peak torque is similar for petrol and diesel but the smaller petrol engine has much higher peak power.
A colleague (the same one that had the diesel Skoda) now has a petrol Golf with a low pressure turbo. That produces tons of torque, and being a petrol engine revs cleanly and smoothly past 6000rpm with a very flat torque curve, so it keeps pulling and pulling. The Skoda vrs made masses of torque and accelerated very fast, but cried enough at 4000 or so and it was time to grab the next gear, and the next, and the next...
Oh and didn't a diesel Audi win some very major races recently?
edit: there it is
http://www.leftlanenews.com/audi-diesel-electric-hybrid-wins-24-hours-of-le-mans.html
I am sure I'd seen some more
Motorsport, my specialist subject

and what's more, endurance racing
The regulations in LMP1 at present favour diesels. The ACO still haven't got it right to achieve balance, although the fact that for several years the manufacturer teams were all been running diesels and it is only with recent the arrival of the Toyota TS030 that Audi and Peugeot have been shown some proper competition (Peugeot have stopped playing). With the Toyota programme entering its second full year this year and hopefully with the teething troubles ironed out, and Porsche also coming to play with their own LMP1 contender in 2014 we should get a much better idea of the diesel vs petrol equivalence in the LMP1 regulations. I can carry on talking about endurance racing for some time, if you wish, if I go to one motor race in the UK in a year it will be the six hours of Silverstone WEC round, and if I could stay awake for 24h straight I would watch the whole of Le Mans each year.
At a more amateur level, diesel vs petrol equivalence is something that I have been a party to making regulations about in the motorsport discipline I compete in (not racing, I don't have that much money) in my corner of the country over the last decade. In what's called the "roadgoing" category, which means MOTed cars in road legal condition, but engine tuning allowed (engine swaps not allowed), suspension improvements etc etc, in against the clock competition on sealed surfaces (race tracks are one example, but we also have events on uphill courses as well) for a long time we ran with up to 1400cc naturally aspirated petrol engined cars competing against up to 2000cc turbo diesel cars. Over the course of several years with a couple of dozen events a year at different venues, I think the class win went to a diesel once. With the advances in diesel engines it's now 1400cc natural aspirated vs 1400cc turbo diesel. Diesels are not as fast, despite being able to run as much boost / intercooling / etc as they want, while the petrol cars are moved out of the class if they fit a turbo into the next capacity class up.
Like for like, petrol engines win in motorsport, which is why diesels get a handicap advantage in direct competition, to help them catch up.