The advent of Ultra Low Sulfur Diesel fuel has enabled improved air quality for diesel powerplants. In fact, they run cleaner than comparable gasoline models. Additionally, diesel engines produce more torque and are more fuel-efficient than gasoline engines of similar displacement. According to the Environmental Protection Agency, diesels typically score 30 to 35 percent better fuel efficiency. Further, today’s new noise- and vibration-damping technologies have also made diesel engines quieter and smoother than in the past. These cars represent the best of the breed.