The first model using Audi's PPE 800-volt platform launches in standard and SQ6 trim with up to 510 horsepower.
Rivian recently filed a trademark for R1X, hinting at an off-road version of its large R1T pickup truck and R1S SUV.
The new GT55 coupe costs about as much as a Porsche 911 Carrera 4S, while the 577-hp GT63 rings in at $177,050.