Oh! So much fun!
Let's see... 2,566 kg for two motors. Even throwing away a huge amount in packaging... say 1/3rd... that's 1,710 kg. Each motor is 855 kg or 1,885 pounds. Hmm... that's pretty close to one of the major errors in the Hawkins paper, "Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles." They "accidentally" modeled their environmental impact with a stationary cast iron industrial motor that almost outweighed the Nissan Leaf they were trying to approximate.
The lightest Model S (60 kWh) weight 1,961 kg or 4,323 pounds. These motors weight about 43% of that. The curb weight of the dual motor 60D is 2,085 kg, or 4,597 lbs. The entire additional weight for the additional motor, inverter, and wiring is 124 kg, or 274 pounds. This motor is 7 times heavier.