Here’s an interesting factoid: did you know that the man who managed the engine development programme for the original E30 BMW M3 is now batting for the opposition? That’s Audi, I hasten to add. Wolfgang Hatz is his name, and I met him this weekend, just after driving the R8 V12 TDi concept.

He’s a thoroughly nice bloke (despite appearances in this rather twee Audi press photo) and at the same time a bit of a motor industry legend. After leaving BMW in the late 1980s, he went to work for Porsche and worked on the 964 RSR, among other projects. After that, he had a spell in race engineering, both for Porsche and General Motors, and then went off to Italy, to be responsible for Alfa Romeo engines, and ultimately all of Fiat Group engines. Then, seven years ago, he decided to make the move back to Germany, and is now responsible for all VW Group engines.

He’s a connected feller. His boss is Ferdinand Piech, he’s best mates with Wolfgang Rietzle, a friend of Luca de Montezemolo – in short, he is the sort of bloke that you wish you could sit next to every Saturday night at dinner; a real dyed-in-the-wool car enthusiast, whose conversational titbits are dining-out fodder for months to come.

So do you think it would bother M-power aficionados to know that the man responsible for arguably the finest performance engine that BMW has ever produced now prefers diesels? To be bluntly honest, it upset me a bit. Here’s how Hatz rationalises it:

“I used to love gasoline engines: my passion was always about power and revs, and so BMW and Porsche were like paradise for me. But then, when I moved to Fiat, I had to learn to love diesel, because this is what Fiat does. And I haven’t been the same since.”

“These days I dream about diesel engines; for me, they have such huge potential, and they’re so challenging. It’s where the real breakthroughs are being made – the territory that is really being fought for right now. As an engineer, that fires you up, you know?”

So does this mean he’s turned his back on petrol totally? “No, of course not. When I look back over my time at Audi, I can pick out several great petrol engines that I’m proud that we made. The RS4’s V8 is probably the biggest achievement personally, because all my old colleagues at BMW said we couldn’t do a good, high-rpm engine. It felt great to prove them wrong.”

“The new Lamborghini direct inject engine, from the LP560-4 – this is great too,” he went on. “You’re going to love it; I’d say it’s twice as good as the old V10.”

And what of this new V12 diesel, soon to come to an R8 near you? “Yeah, this is the car I dream about now. I want, more than anything else, to make this car happen for Audi. It’s really only us that can make a diesel supercar, you know, and that’s why I think we must.”

It won’t be easy for him. There are cost savings to be made, there is new componentry to be developed, and business cases to make watertight. “We have two options with this car: make it a low-volume, higher price car, which might give us a higher development budget, or to do unlimited volume for a lower price, and then work to a lower price. The marketing men will tell us which within the next few months.”

But will that make the R8 V12 TDi the range-topping option in the range? “No, there will be a faster gasoline one.”

“With a new, high rpm V10,” I asked.

“No, guess again.”

“The twin-turbo, 572bhp RS6 V10? In an R8? Next year? Really?”

Hatz just smiled and nodded (that’s how Autocar news scoops are made these days).

And does it matter, then, that Audi will make a more powerful R8 than Lambo’s Gallardo? “We will wait and see,” Wolfgang replied.