there isnt a demand for a high performance diesel, Audi are pushing diesel for their road car sales.
The Clubsport was a concept showing a tuned 2.0tdi engine but the R8 V12tdi has been shelved for now.
IF I was going to buy a high performance engine, I want to HEAR it rev to 7-9k revs, not up changing between 2-3k revs, also as said the power band is very narrow with diesels.
besides the torque of bigger diesels is far better than high revving engines anyway BUT then the transmission cant take it
so its a split between developing a transmission that wont tie itself into a box of knots at the first hot start from the lights and an engine that can be reliable and rev its tits off
the R8 V12tdi is shelved until someone develops the transmission to handle the massive torque generated, the box fitted to the concept car would last 100 yards if it was given the beans, ( quote Autocar showpiece article of the car in Miami).