IL Insider: Audi Going With V6 Instead of V8 in Next S5

"Not only does this new engine get nearly the same horsepower and more torque," said an Audi spokesperson, "but the fuel efficiency with the V6T improves by 30 percent over the V8." The current S5 has been given lukewarm reviews at best for its power and torque curves, not to mention its weight. The much lighter V6T engine can be expected to be a big improvement in those areas.

The next Audi S6 will swap its V10 for an updated twin-turbocharged version of the 4.2-liter V8. Audi will likely make the same move for the S8, leaving the V10 biturbo version to the higher-performance R8 coming next year — and to the racing R8 GT being worked over by Audi racing guru Abt Sportsline.

Within two years, the V6 turbo will also go into the much-talked-about R4 midengine two-seater. The base R8 will stick with the updated V8 to be seen in the next S6. As for the R8 V12 TDI, it should go into production pretty much as IL drove it in prototype form early this year.

Rumors abound of an R6 roadster to lodge in between the R4 and R8 and of the often spotted TT-RS street racer, also coming sometime in 2009.

As IL has reported previously, Audi's future RS4, RS6 and new RS5 will all be lighter in weight and are all intended first and foremost for the U.S. market. "We're shooting for Porsches," said an engineer, speaking to IL on condition of anonymity.

Inside Line says: It'll be fun to see how the intermixed Porsche-VW-Audi development program develops and to watch as Audi goes for its share of street cred at last. — Matt Davis, Correspondent