An engineer on the project said that the new SL should go on sale in 2021 with four engine options. The SL43 would borrow the 3.0-liter inline-six with 435 hp from new . Like the CLS 53 AMG, this engine will be combined with a 48V mild hybrid system. Strangely, the SL53 would be different from the other 53 models and use a 4.0-liter twin-turbo V8 with 522 hp combined with a 48V mild hybrid system. The SL63 would also use a 4.0-liter twin-turbo V8 with a mild hybrid system, but with 612 hp. Finally, the SL73 would use a 4.0-liter twin-turbo V-8 with 612 hp, combined with an e-motor rated at 204 hp. Total output would be more than 800 hp and 738 lb-ft of torque.