Audi adds 420-HP 4.0T V8 to A8, upgraded 3.0L TDI to Q7 for 2013
The Audi A8 will be ditching its tried-and-true naturally aspirated 4.2-liter V8 engine for the 2013 model year. Instead, the automaker is fitting its flagship sedan with the twin-turbocharged 4.0-liter V8 that's also being used in the S6 and S7, good for...