In January 2003, Lexus unveiled the second-generation RX model - the car's design remained very similar, but the lines became noticeably softer and more sleek in shape. The new model has an air resistance factor of Cd 0.35. New engines were introduced, the most powerful of which is the modern 3.5-liter V6 petrol engine in the RX 350 with variable valve timing (VVT-i) technology developing 200 kW at 6200 rpm and 342 Nm of torque at 4700 rpm. The Lexus RX 400 features Lexus Hybrid Drive, which combines a V6 petrol engine with an electric motor. When sudden acceleration is required, the petrol engine and electric motors run together, generating electricity during braking and used to charge the battery. At low speeds, only an electric motor is used, which means that the car makes almost no noise and does not emit any harmful gases into the environment. The second-generation Lexus RX remained in high demand and became the most popular luxury car in the United States.