Ok, so we know about the supposed 57 horsepower difference (per Pescarolo)
But here is what we should take a look at. For this example let's look at the BMW 3 series coupes, one with diesel the other with gasoline engine. Both have inline 6 cylinder engines with twin turbos. The diesel one is 2993cc and the gasoline twin turbo displaces 2979cc.
http://www.bmw.co.uk/bmwuk/pricesand...-bmwuk,00.html
The diesel makes 286 horsepower @ 4400 RPM and 580 NM torque @ 1750 RPM. 0-62 acceleration is in 6.1 seconds, combined fuel economy of 37.7 (British) mpg.
The gasoline engine makes 306 horsepower @ 5800 RPM and 400 NM of torque @ 1300 RPM. 0-62 acceleration in 5.7 seconds (with automatic like the diesel engine) Combined fuel economy of 29.7 (British) mpg.
The diesel 3 series coupe is 30 kg heavier and probably runs more boost.