thank you Wutputt for getting that diesel power issue straight before I got to it

saved me a lot of words
the problem with diesel engines isn't the fuel, just how they combust. since they basically run by detonation, it limits the max rpms of the engine. If someone was to somehow design a high revving sports diesel with the same combustion precision of modern gasoline engines, it would decimate the competition.
as for putting a diesel in a sportscar, like an sl, imo that's pretty stupid. diesel is kind of the anti-sport in terms of image, and that's what those cars are all about
might sell well in UK tho