Autoweek and Fourtitude were able to enjoy some seat time in the Audi R8 V12 TDI LeMans concept before its official unveiling in Geneva last week. Their drive was short (about an hour with a 50 mph speed limit imposed by Audi's boffins), but their time at the airport adjacent to Sebring International Raceway has made an impression.The crimson beast we saw in Geneva was the same concept that was displayed in Detroit , simply sporting a new paint job, but spending quality time with the R8 V12 TDI revealed a few interesting tidbits about the concept. First, the firewall behind the driver and passenger had to be extended by some six-inches to accommodate the oilburner and although claimed torque output is somewhere in the 737 lb.-ft. range, the few journos asked to take part only got to experience 442 lb.-ft. of twist – a good thing considering that the transmission mated to the engine is an A4 case with modified internals.While the performance was impressive, the short gearing and shorter redline (not disclosed) seemed to make all that grunt superfluous in first and second, but Audi is expecting the R8 V12 TDI to return around 24 mpg and meet the 2014 Euro 6 emissions standards if, and when, it goes on sale.While the Autoweek piece only provided the "50/50" quote in the title, the Fourtitude article is far more entertaining and informative -- well worth a read