 The engine options at the launch are 3.0-litre turbo I6 (GLS 450 4MATIC) and 4.0-litre twin-turbo V8 (GLS 580 4MATIC), both petrol with EQ Boost electric motors, and 2.9-litre twin-turbo diesel I6 in two different outputs (GLS 350 d 4MATIC and GLS 400 d 4MATIC).A GLS 600 Maybach model was released in late 2019.The wheelbase is 2.3 inches longer and nearly an inch wider.