Audi will launch the A6 E-Tron this summer, its second model after the Q6 E-Tron to ride on parent company Volkswagen Group’s new PPE dedicated EV platform. The A6 E-Tron will be a Tesla Model S rival capable of delivering at least 300 miles of range, and both S6 and RS 6 performance variants are in the pipeline. Bentley’s W-12 engine has ceased…