Car & Driver's Mike Dushane nabbed a one-on-one interview with Audi AG head of development Michael Dick. It's a great article and a must-read, but here're the most interesting portions according to us...
Next-Gen S5 and S4
We're calling it B9, but it'll be an evolution of Audi's MLB (modular longitudinal architecture). Dick told C&D that the next-gen cars will make heavy use of Audi's aluminum space frame tech as seen in the A8 and TT to drop weight by 20%. That's good for handling and efficiency, but will also allow Audi to offer smaller engines (30% less displacement says the C&D piece) - think turbocharged 4-cylinders.
Michael Dick told C&D that Audi is currently testing a next-gen mule that weighs 880 lbs less than the current car.... roughly 3000 lbs... about 100 lbs. lighter than a last-gen Subaru Impreza WRX STI. The Audi board member also says the mule will lap the Nurburgring 8 seconds faster than the current S5.
For those mule-spotters in Nurburg, the article also mentions the car is wearing the current S5's bodywork.
The S5 is set to debut in 2014 according to the article.
If the article is right, then the next-gen A6 will also utilize an aluminum space frame.